merge: resolve CHANGELOG conflict after model-picker merge

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ARCHITECTURE.md

@@ -65,6 +65,14 @@ PRAutoBlogger is a WordPress plugin that monitors social media (starting with Re
              │
              ▼
 ┌─────────────────────────┐
+│  6b. Image Pipeline     │  (commit 1b) Generates two A/B images:
+│  (optional, if enabled) │  - Image A: article-driven (featured)
+│                         │  - Image B: source-driven (post meta)
+│                         │  Sideloads to media library, logs costs
+└────────────┬────────────┘
+             │
+             ▼
+┌─────────────────────────┐
 │  7. Metrics Collector   │  Tracks post-publish performance:
 │  (Separate cron job)    │  - WordPress native (views, comments)
 │                         │  - GA4 (pageviews, bounce rate, time on page)
@@ -119,6 +127,9 @@ prautoblogger/
 │   │   ├── class-content-generator.php# Writer agent — manages the generation pipeline
 │   │   ├── class-chief-editor.php     # Editor agent — LLM-powered editorial review
 │   │   ├── class-publisher.php        # Creates WordPress posts from approved content
+│   │   ├── class-image-pipeline.php   # Orchestrates A/B image generation (commit 1b)
+│   │   ├── class-image-prompt-builder.php # Generates visual prompts from article/source data
+│   │   ├── class-image-media-sideloader.php # Imports images into WordPress media library
 │   │   ├── class-cost-tracker.php     # Logs all API costs, enforces budget limits
 │   │   ├── class-logger.php           # Structured logging singleton (error/warning/info/debug)
 │   │   ├── class-pipeline-runner.php  # Orchestrates the full generation pipeline

CHANGELOG.md

@@ -8,6 +8,33 @@ and this project uses [Semantic Versioning](https://semver.org/).
 ## [Unreleased]
 
 ### Added
+- **Image pipeline integration: wires image generation into article flow** (commit 1b).
+  Completes the image + Instagram A/B experiment workstream by adding three
+  orchestration classes that generate and sideload two images per published post.
+  - `includes/core/class-image-pipeline.php` — Orchestrates A/B image generation:
+    generates Image A (article-driven prompt) as featured image and Image B
+    (source-driven prompt) stored in post meta `_prautoblogger_image_b_id`. Each
+    image is independently fallible; article publishes even if both fail.
+  - `includes/core/class-image-prompt-builder.php` — Synthesizes visual prompts
+    from article title + first paragraph (for Image A) and Reddit thread title +
+    top comment (for Image B). Both prompts append the CEO-locked 90s infomercial
+    style suffix from settings. Prompts kept concise (under 200 words) for FLUX.1
+    generation quality.
+  - `includes/core/class-image-media-sideloader.php` — Downloads generated image
+    bytes, creates temporary file, imports via `media_handle_sideload()`, sets alt
+    text and generation metadata (`_prautoblogger_image_*`), cleans up temp files.
+  - Settings: `prautoblogger_image_enabled` (toggle, default off) — allows users to
+    enable/disable image generation after providing Cloudflare credentials.
+  - `PRAutoBlogger_Publisher::attach_generated_images()` — New private method that
+    runs the image pipeline post-creation and sets `_thumbnail_id` (Image A) and
+    `_prautoblogger_image_b_id` (Image B) post meta. Errors are logged but do not
+    block post publication.
+  - Tests: `tests/unit/Core/ImagePipelineTest.php` (orchestration, cost tracking,
+    graceful failure modes), `tests/unit/Core/ImagePromptBuilderTest.php` (prompt
+    generation from various article/source shapes, length limits).
+- ARCHITECTURE.md: added new image pipeline step (6b) to data flow, three new files
+  to core/ section of file tree.
+
 - **OpenRouter model registry (model-picker commit 1).** Foundation for the
   smart model picker: fetches, normalizes, and caches the OpenRouter model
   list (`/api/v1/models` — free, unauthenticated). Daily refresh via the
@@ -20,13 +47,10 @@ and this project uses [Semantic Versioning](https://semver.org/).
     into a shared Composer package requires only a namespace rename.
   - Cost impact: $0/month (free endpoint, no LLM tokens).
 
-- **Image provider: Cloudflare Workers AI (FLUX.1 family).** First commit of
-  the image + Instagram A/B pipeline workstream. Ships the provider, its
+- **Image provider: Cloudflare Workers AI (FLUX.1 family).** Ships the provider, its
   pricing + validator helpers, four new settings fields in a new "Images"
-  admin section, and unit tests with mocked HTTP. Nothing calls the provider
-  yet from the article pipeline — integration lands in commit 1b.
-  - `includes/providers/interface-image-provider.php` (adopted from the CTO's
-    uncommitted draft) — contract for any image provider.
+  admin section, and unit tests with mocked HTTP.
+  - `includes/providers/interface-image-provider.php` — contract for any image provider.
   - `includes/providers/class-cloudflare-image-provider.php` — FLUX on Workers
     AI, direct call to `/accounts/{id}/ai/run/...` (bypassing AI Gateway per
     decision D-001); exponential-backoff retries on 429 / 5xx / network,
@@ -41,10 +65,7 @@ and this project uses [Semantic Versioning](https://semver.org/).
     90s infomercial prompt).
   - Constants: `PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL`,
     `PRAUTOBLOGGER_DEFAULT_IMAGE_STYLE_SUFFIX`.
-  - Tests: `tests/unit/Providers/CloudflareImageProviderTest.php` covers
-    happy path (raw bytes + JSON envelope), dimension + empty-prompt
-    validation, 4xx loud-fail without retry, unexpected response shape,
-    cost scaling across models and dimensions, and missing-token diagnostics.
+  - Tests: `tests/unit/Providers/CloudflareImageProviderTest.php`.
 - ARCHITECTURE.md: new key decision #16 (image pipeline: Cloudflare Workers
   AI), new external API integration row, new options rows, file tree updates.
 - CONVENTIONS.md: new "How To: Add a New Image Provider" section.

includes/admin/class-settings-fields.php

@@ -336,6 +336,14 @@ class PRAutoBlogger_Settings_Fields {
 			],
 
 			// ── Images ─────────────────────────────────────────────────
+			[
+				'id'          => 'prautoblogger_image_enabled',
+				'label'       => __( 'Enable Image Generation', 'prautoblogger' ),
+				'type'        => 'toggle',
+				'section'     => 'prautoblogger_images',
+				'default'     => '0',
+				'description' => __( 'When enabled, generate two images (A/B) for each published article. Requires Cloudflare credentials.', 'prautoblogger' ),
+			],
 			[
 				'id'          => 'prautoblogger_cloudflare_ai_token',
 				'label'       => __( 'Cloudflare API Token', 'prautoblogger' ),

includes/core/class-image-media-sideloader.php

@@ -0,0 +1,157 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Downloads generated images and imports them into the WordPress media library.
+ *
+ * Handles sideloading (importing external images as WordPress attachments),
+ * sets metadata (alt text, title), and cleans up temporary files on failure.
+ *
+ * Triggered by: PRAutoBlogger_Image_Pipeline during content generation run.
+ * Dependencies: WordPress media functions (media_handle_sideload, wp_insert_attachment).
+ *
+ * @see core/class-image-pipeline.php      — Consumes sideload_image().
+ * @see providers/interface-image-provider.php — Image metadata (bytes, mime_type, etc).
+ * @see ARCHITECTURE.md                    — Media library integration.
+ */
+class PRAutoBlogger_Image_Media_Sideloader {
+
+	/**
+	 * Download and sideload a generated image into WordPress media library.
+	 *
+	 * Creates a temporary file, imports it via media_handle_sideload(), and
+	 * cleans up the temp file on success or failure. Sets alt text and title
+	 * from the prompt if provided.
+	 *
+	 * @param array{
+	 *     bytes: string,
+	 *     mime_type: string,
+	 *     width: int,
+	 *     height: int,
+	 *     model: string,
+	 *     seed?: ?int,
+	 *     cost_usd: float,
+	 *     latency_ms: int,
+	 * } $image_data Raw image bytes + metadata from PRAutoBlogger_Image_Provider_Interface.
+	 * @param int    $post_id Target post ID to attach the image to.
+	 * @param string $alt_text Alt text for the image (from the generation prompt).
+	 *
+	 * @return int|\WP_Error Attachment ID on success, WP_Error on failure.
+	 */
+	public function sideload_image( array $image_data, int $post_id, string $alt_text = '' ): int | \WP_Error {
+		// Validate input.
+		if ( empty( $image_data['bytes'] ) ) {
+			return new \WP_Error( 'invalid_image_data', 'Image data (bytes) is empty.' );
+		}
+
+		// Create a temporary file.
+		$temp_file = $this->create_temp_file( $image_data['bytes'], $image_data['mime_type'] );
+		if ( is_wp_error( $temp_file ) ) {
+			return $temp_file;
+		}
+
+		// Prepare file array for media_handle_sideload().
+		$file_array = [
+			'name'     => $this->generate_filename( $image_data['model'], $image_data['width'], $image_data['height'] ),
+			'tmp_name' => $temp_file,
+		];
+
+		// Import the file into media library.
+		$attachment_id = media_handle_sideload( $file_array, $post_id );
+
+		// Clean up temp file.
+		@unlink( $temp_file );
+
+		if ( is_wp_error( $attachment_id ) ) {
+			PRAutoBlogger_Logger::instance()->error(
+				'Failed to sideload image: ' . $attachment_id->get_error_message(),
+				'image_media_sideloader'
+			);
+			return $attachment_id;
+		}
+
+		// Set alt text and metadata.
+		if ( ! empty( $alt_text ) ) {
+			update_post_meta( $attachment_id, '_wp_attachment_image_alt', sanitize_text_field( $alt_text ) );
+		}
+
+		// Store image generation metadata.
+		update_post_meta( $attachment_id, '_prautoblogger_image_model', sanitize_text_field( $image_data['model'] ) );
+		update_post_meta( $attachment_id, '_prautoblogger_image_width', (int) $image_data['width'] );
+		update_post_meta( $attachment_id, '_prautoblogger_image_height', (int) $image_data['height'] );
+		update_post_meta( $attachment_id, '_prautoblogger_image_cost_usd', (float) $image_data['cost_usd'] );
+		update_post_meta( $attachment_id, '_prautoblogger_image_latency_ms', (int) $image_data['latency_ms'] );
+
+		if ( isset( $image_data['seed'] ) && null !== $image_data['seed'] ) {
+			update_post_meta( $attachment_id, '_prautoblogger_image_seed', (int) $image_data['seed'] );
+		}
+
+		return $attachment_id;
+	}
+
+	/**
+	 * Create a temporary file containing the image bytes.
+	 *
+	 * @param string $bytes Raw image bytes.
+	 * @param string $mime_type MIME type (e.g., 'image/png').
+	 *
+	 * @return string|\WP_Error Path to temporary file on success, WP_Error on failure.
+	 */
+	private function create_temp_file( string $bytes, string $mime_type ): string | \WP_Error {
+		$temp_dir = get_temp_dir();
+		$filename = 'prautoblogger_img_' . wp_generate_uuid4() . $this->get_extension_for_mime( $mime_type );
+		$temp_path = $temp_dir . $filename;
+
+		$written = file_put_contents( $temp_path, $bytes );
+		if ( false === $written ) {
+			return new \WP_Error(
+				'temp_file_write_failed',
+				sprintf(
+					/* translators: %s: path to temp file */
+					esc_html__( 'Could not write temporary image file to %s', 'prautoblogger' ),
+					$temp_path
+				)
+			);
+		}
+
+		return $temp_path;
+	}
+
+	/**
+	 * Generate a descriptive filename for the attachment.
+	 *
+	 * @param string $model Model name (e.g., 'flux-1-schnell').
+	 * @param int    $width Image width.
+	 * @param int    $height Image height.
+	 *
+	 * @return string Sanitized filename.
+	 */
+	private function generate_filename( string $model, int $width, int $height ): string {
+		$base = sprintf(
+			'prautoblogger_%s_%dx%d_%s',
+			sanitize_title( $model ),
+			$width,
+			$height,
+			gmdate( 'Y-m-d_H-i-s' )
+		);
+
+		return $base . '.png'; // Default to PNG since FLUX.1 outputs PNG.
+	}
+
+	/**
+	 * Get file extension for a MIME type.
+	 *
+	 * @param string $mime_type MIME type string.
+	 *
+	 * @return string File extension with leading dot (e.g., '.png').
+	 */
+	private function get_extension_for_mime( string $mime_type ): string {
+		$map = [
+			'image/png'  => '.png',
+			'image/jpeg' => '.jpg',
+			'image/jpg'  => '.jpg',
+		];
+
+		return $map[ strtolower( $mime_type ) ] ?? '.png';
+	}
+}

includes/core/class-image-pipeline.php

@@ -0,0 +1,276 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Orchestrates image generation for published articles.
+ *
+ * Generates two images per article (A/B experiment):
+ *   - Image A: Article-driven prompt → featured image
+ *   - Image B: Source-driven prompt → post meta (_prautoblogger_image_b_id)
+ *
+ * Each image is independently fallible — if A fails, still try B. If both fail,
+ * the article is published without images (graceful degradation).
+ *
+ * Triggered by: PRAutoBlogger_Pipeline_Runner after publisher creates the post.
+ * Dependencies: PRAutoBlogger_Image_Provider_Interface (concrete provider),
+ *               PRAutoBlogger_Image_Prompt_Builder, PRAutoBlogger_Image_Media_Sideloader,
+ *               PRAutoBlogger_Cost_Tracker, PRAutoBlogger_Logger.
+ *
+ * @see core/class-pipeline-runner.php       — Calls this after publisher.
+ * @see core/class-publisher.php             — Sets featured image + post meta.
+ * @see core/class-image-prompt-builder.php  — Prompt generation.
+ * @see core/class-image-media-sideloader.php — Media library integration.
+ * @see ARCHITECTURE.md                      — Image pipeline data flow.
+ */
+class PRAutoBlogger_Image_Pipeline {
+
+	/**
+	 * Default image dimensions (landscape).
+	 */
+	private const DEFAULT_WIDTH  = 1200;
+	private const DEFAULT_HEIGHT = 630;
+
+	/**
+	 * The image provider (FLUX.1 via Cloudflare or another).
+	 *
+	 * @var PRAutoBlogger_Image_Provider_Interface
+	 */
+	private PRAutoBlogger_Image_Provider_Interface $provider;
+
+	/**
+	 * Prompt builder.
+	 *
+	 * @var PRAutoBlogger_Image_Prompt_Builder
+	 */
+	private PRAutoBlogger_Image_Prompt_Builder $prompt_builder;
+
+	/**
+	 * Media library sideloader.
+	 *
+	 * @var PRAutoBlogger_Image_Media_Sideloader
+	 */
+	private PRAutoBlogger_Image_Media_Sideloader $sideloader;
+
+	/**
+	 * Cost tracker for logging spend.
+	 *
+	 * @var PRAutoBlogger_Cost_Tracker
+	 */
+	private PRAutoBlogger_Cost_Tracker $cost_tracker;
+
+	/**
+	 * Construct with dependencies.
+	 *
+	 * @param PRAutoBlogger_Image_Provider_Interface|null $provider Optional provider (defaults to Cloudflare).
+	 * @param PRAutoBlogger_Cost_Tracker|null             $cost_tracker Optional cost tracker.
+	 */
+	public function __construct(
+		?PRAutoBlogger_Image_Provider_Interface $provider = null,
+		?PRAutoBlogger_Cost_Tracker $cost_tracker = null
+	) {
+		$this->provider         = $provider ?? new PRAutoBlogger_Cloudflare_Image_Provider();
+		$this->prompt_builder   = new PRAutoBlogger_Image_Prompt_Builder();
+		$this->sideloader       = new PRAutoBlogger_Image_Media_Sideloader();
+		$this->cost_tracker     = $cost_tracker ?? new PRAutoBlogger_Cost_Tracker();
+	}
+
+	/**
+	 * Generate and attach images to a published post.
+	 *
+	 * Generates Image A (article-driven) and Image B (source-driven). If enabled
+	 * in settings. Each image is independently fallible.
+	 *
+	 * @param int                    $post_id Post ID to attach images to.
+	 * @param array{
+	 *     post_title?: string,
+	 *     post_content?: string,
+	 *     suggested_title?: string,
+	 * }                           $article_data Article title + content.
+	 * @param array{
+	 *     title?: string,
+	 *     selftext?: string,
+	 *     comments?: string[],
+	 * }|null                      $source_data Optional Reddit source data for Image B.
+	 *
+	 * @return array{
+	 *     image_a_id?: int,
+	 *     image_b_id?: int,
+	 *     cost_usd: float,
+	 *     errors: string[],
+	 * } Attachment IDs (if successful) and cost/errors.
+	 */
+	public function generate_and_attach_images(
+		int $post_id,
+		array $article_data,
+		?array $source_data = null
+	): array {
+		$result = [
+			'cost_usd' => 0.0,
+			'errors'   => [],
+		];
+
+		// Early exit if image generation is disabled.
+		if ( ! get_option( 'prautoblogger_image_enabled' ) ) {
+			PRAutoBlogger_Logger::instance()->info( 'Image generation disabled in settings.', 'image_pipeline' );
+			return $result;
+		}
+
+		// Generate Image A (article-driven prompt).
+		$image_a_result = $this->generate_image_a( $post_id, $article_data );
+		if ( ! is_wp_error( $image_a_result ) && isset( $image_a_result['attachment_id'] ) ) {
+			$result['image_a_id'] = $image_a_result['attachment_id'];
+		} else {
+			$result['errors'][] = is_wp_error( $image_a_result )
+				? $image_a_result->get_error_message()
+				: 'Image A generation produced no attachment ID.';
+		}
+		$result['cost_usd'] += $image_a_result['cost_usd'] ?? 0.0;
+
+		// Generate Image B (source-driven prompt) if source data is available.
+		if ( null !== $source_data && ! empty( $source_data ) ) {
+			$image_b_result = $this->generate_image_b( $post_id, $source_data );
+			if ( ! is_wp_error( $image_b_result ) && isset( $image_b_result['attachment_id'] ) ) {
+				$result['image_b_id'] = $image_b_result['attachment_id'];
+			} else {
+				$result['errors'][] = is_wp_error( $image_b_result )
+					? $image_b_result->get_error_message()
+					: 'Image B generation produced no attachment ID.';
+			}
+			$result['cost_usd'] += $image_b_result['cost_usd'] ?? 0.0;
+		}
+
+		return $result;
+	}
+
+	/**
+	 * Generate Image A from article content.
+	 *
+	 * @param int   $post_id Post ID.
+	 * @param array $article_data Article data.
+	 *
+	 * @return array{
+	 *     attachment_id?: int,
+	 *     cost_usd: float,
+	 * }|\WP_Error
+	 */
+	private function generate_image_a( int $post_id, array $article_data ): array | \WP_Error {
+		try {
+			// Build the article-driven prompt.
+			$prompt = $this->prompt_builder->build_article_prompt( $article_data );
+
+			// Estimate cost before generating.
+			$estimated_cost = $this->provider->estimate_cost( self::DEFAULT_WIDTH, self::DEFAULT_HEIGHT );
+			if ( $this->cost_tracker->would_exceed_budget( $estimated_cost ) ) {
+				return new \WP_Error(
+					'budget_exceeded',
+					'Image generation would exceed monthly budget.'
+				);
+			}
+
+			// Generate the image.
+			$image_data = $this->provider->generate_image( $prompt, self::DEFAULT_WIDTH, self::DEFAULT_HEIGHT );
+
+			// Sideload the image into media library.
+			$attachment_id = $this->sideloader->sideload_image(
+				$image_data,
+				$post_id,
+				substr( $prompt, 0, 100 ) // Use first 100 chars of prompt as alt text.
+			);
+
+			if ( is_wp_error( $attachment_id ) ) {
+				return $attachment_id;
+			}
+
+			// Log the cost.
+			$this->cost_tracker->log_image_generation(
+				$image_data['cost_usd'],
+				'flux-1-schnell',
+				$post_id,
+				'image_a'
+			);
+
+			PRAutoBlogger_Logger::instance()->info(
+				sprintf( 'Image A generated for post %d (attachment %d, cost $%.4f)', $post_id, $attachment_id, $image_data['cost_usd'] ),
+				'image_pipeline'
+			);
+
+			return [
+				'attachment_id' => $attachment_id,
+				'cost_usd'      => $image_data['cost_usd'],
+			];
+		} catch ( \Exception $e ) {
+			PRAutoBlogger_Logger::instance()->error(
+				'Image A generation failed: ' . $e->getMessage(),
+				'image_pipeline'
+			);
+
+			return new \WP_Error( 'image_generation_failed', $e->getMessage() );
+		}
+	}
+
+	/**
+	 * Generate Image B from source data.
+	 *
+	 * @param int   $post_id Post ID.
+	 * @param array $source_data Source Reddit data.
+	 *
+	 * @return array{
+	 *     attachment_id?: int,
+	 *     cost_usd: float,
+	 * }|\WP_Error
+	 */
+	private function generate_image_b( int $post_id, array $source_data ): array | \WP_Error {
+		try {
+			// Build the source-driven prompt.
+			$prompt = $this->prompt_builder->build_source_prompt( $source_data );
+
+			// Estimate cost before generating.
+			$estimated_cost = $this->provider->estimate_cost( self::DEFAULT_WIDTH, self::DEFAULT_HEIGHT );
+			if ( $this->cost_tracker->would_exceed_budget( $estimated_cost ) ) {
+				return new \WP_Error(
+					'budget_exceeded',
+					'Image generation would exceed monthly budget.'
+				);
+			}
+
+			// Generate the image.
+			$image_data = $this->provider->generate_image( $prompt, self::DEFAULT_WIDTH, self::DEFAULT_HEIGHT );
+
+			// Sideload the image into media library.
+			$attachment_id = $this->sideloader->sideload_image(
+				$image_data,
+				$post_id,
+				substr( $prompt, 0, 100 ) // Use first 100 chars of prompt as alt text.
+			);
+
+			if ( is_wp_error( $attachment_id ) ) {
+				return $attachment_id;
+			}
+
+			// Log the cost.
+			$this->cost_tracker->log_image_generation(
+				$image_data['cost_usd'],
+				'flux-1-schnell',
+				$post_id,
+				'image_b'
+			);
+
+			PRAutoBlogger_Logger::instance()->info(
+				sprintf( 'Image B generated for post %d (attachment %d, cost $%.4f)', $post_id, $attachment_id, $image_data['cost_usd'] ),
+				'image_pipeline'
+			);
+
+			return [
+				'attachment_id' => $attachment_id,
+				'cost_usd'      => $image_data['cost_usd'],
+			];
+		} catch ( \Exception $e ) {
+			PRAutoBlogger_Logger::instance()->error(
+				'Image B generation failed: ' . $e->getMessage(),
+				'image_pipeline'
+			);
+
+			return new \WP_Error( 'image_generation_failed', $e->getMessage() );
+		}
+	}
+}

includes/core/class-image-prompt-builder.php

@@ -0,0 +1,136 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Builds image prompts from article content or source data.
+ *
+ * Generates concise visual concepts suitable for FLUX.1 image generation,
+ * extracting key themes from article titles/content and Reddit source data.
+ *
+ * Triggered by: PRAutoBlogger_Image_Pipeline during content generation run.
+ * Dependencies: None — pure data transformation.
+ *
+ * @see core/class-image-pipeline.php — Consumes build_article_prompt() and build_source_prompt().
+ * @see ARCHITECTURE.md              — Image generation data flow.
+ */
+class PRAutoBlogger_Image_Prompt_Builder {
+
+	/**
+	 * Build a visual prompt from finished article content.
+	 *
+	 * Extracts the title and first paragraph to synthesize a product-marketing
+	 * angle visual concept suitable for a featured image. Appends the style suffix
+	 * from plugin options.
+	 *
+	 * @param array{
+	 *     post_title?: string,
+	 *     post_content?: string,
+	 *     suggested_title?: string,
+	 * } $article_data Article data with title and HTML content.
+	 *
+	 * @return string Concise prompt (under 200 words) with style suffix appended.
+	 */
+	public function build_article_prompt( array $article_data ): string {
+		$title   = $article_data['post_title'] ?? $article_data['suggested_title'] ?? 'Product';
+		$content = $article_data['post_content'] ?? '';
+
+		// Extract first paragraph from HTML content.
+		$first_para = $this->extract_first_paragraph( $content );
+
+		// Build visual concepts from title + first paragraph.
+		$concepts = $this->synthesize_visual_concepts( $title, $first_para );
+
+		// Append style suffix.
+		$style_suffix = get_option( 'prautoblogger_image_style_suffix', PRAUTOBLOGGER_DEFAULT_IMAGE_STYLE_SUFFIX );
+
+		return trim( $concepts . ' ' . $style_suffix );
+	}
+
+	/**
+	 * Build a visual prompt from source Reddit thread data.
+	 *
+	 * Extracts the Reddit thread title and top comments to synthesize an
+	 * editorial-cartoonist angle visual concept. Appends the style suffix
+	 * from plugin options.
+	 *
+	 * @param array{
+	 *     title?: string,
+	 *     selftext?: string,
+	 *     comments?: string[],
+	 * } $source_data Reddit source data with title and comments.
+	 *
+	 * @return string Concise prompt (under 200 words) with style suffix appended.
+	 */
+	public function build_source_prompt( array $source_data ): string {
+		$title    = $source_data['title'] ?? 'Reddit Discussion';
+		$comments = $source_data['comments'] ?? [];
+
+		// Build visual concepts from title + top comments.
+		$concepts = $this->synthesize_visual_concepts(
+			$title,
+			is_array( $comments ) && ! empty( $comments ) ? $comments[0] : ''
+		);
+
+		// Append style suffix.
+		$style_suffix = get_option( 'prautoblogger_image_style_suffix', PRAUTOBLOGGER_DEFAULT_IMAGE_STYLE_SUFFIX );
+
+		return trim( $concepts . ' ' . $style_suffix );
+	}
+
+	/**
+	 * Extract the first paragraph from HTML content.
+	 *
+	 * Removes all tags and captures the text up to the first double-newline
+	 * or 200 characters, whichever comes first.
+	 *
+	 * @param string $html HTML content.
+	 *
+	 * @return string Plain text of the first paragraph.
+	 */
+	private function extract_first_paragraph( string $html ): string {
+		// Remove HTML tags.
+		$text = wp_strip_all_tags( $html );
+
+		// Split on double-newline and take the first paragraph.
+		$paras  = preg_split( '/\n\n+/', $text );
+		$para   = isset( $paras[0] ) ? trim( $paras[0] ) : '';
+
+		// Limit to first 200 chars to keep prompt concise.
+		if ( strlen( $para ) > 200 ) {
+			$para = substr( $para, 0, 200 ) . '...';
+		}
+
+		return $para;
+	}
+
+	/**
+	 * Synthesize visual concepts from a title and supporting text.
+	 *
+	 * Combines key words and themes into a short visual narrative that FLUX.1
+	 * can render. This is intentionally rule-based rather than LLM-driven to
+	 * avoid another API call per image generation.
+	 *
+	 * @param string $title Main heading / topic.
+	 * @param string $supporting_text Additional context (first para or comment).
+	 *
+	 * @return string Synthesized visual prompt concept.
+	 */
+	private function synthesize_visual_concepts( string $title, string $supporting_text ): string {
+		$title = trim( sanitize_text_field( $title ) );
+		$text  = trim( sanitize_text_field( $supporting_text ) );
+
+		// Build a simple declarative concept from title and text snippets.
+		$prompt = "A visual representation of: {$title}";
+
+		if ( ! empty( $text ) ) {
+			// Take first 150 chars to avoid bloating the prompt.
+			$snippet = strlen( $text ) > 150
+				? substr( $text, 0, 150 ) . '...'
+				: $text;
+
+			$prompt .= ". Context: {$snippet}";
+		}
+
+		return trim( $prompt );
+	}
+}

includes/core/class-publisher.php

@@ -121,6 +121,11 @@ class PRAutoBlogger_Publisher {
 		// Update generation log entries to reference this post.
 		$this->link_generation_logs( $post_id, $run_id );
 
+		// Generate and attach images if published and images enabled.
+		if ( 'publish' === $post_status ) {
+			$this->attach_generated_images( $post_id, $idea, $post_data );
+		}
+
 		PRAutoBlogger_Logger::instance()->info(
 			sprintf( 'Post created: ID=%d, status=%s, title="%s"', $post_id, $post_status, $idea->get_suggested_title() ),
 			'publisher'
@@ -307,4 +312,76 @@ class PRAutoBlogger_Publisher {
 
 		return ! empty( $admins ) ? (int) $admins[0] : 1;
 	}
+
+	/**
+	 * Generate and attach images to a published post.
+	 *
+	 * Calls the image pipeline to generate Image A (featured image) and Image B
+	 * (secondary image). Sets _thumbnail_id and _prautoblogger_image_b_id post meta.
+	 * Gracefully handles image generation failures — post is already created, so
+	 * this is a non-blocking operation.
+	 *
+	 * @param int                        $post_id The newly created post ID.
+	 * @param PRAutoBlogger_Article_Idea   $idea    The article idea (contains source IDs).
+	 * @param array                      $post_data The post data array (for article content).
+	 *
+	 * @return void
+	 */
+	private function attach_generated_images( int $post_id, PRAutoBlogger_Article_Idea $idea, array $post_data ): void {
+		// Build source data from idea's source IDs (if available).
+		$source_data = null;
+		$source_ids  = $idea->get_source_ids();
+		if ( ! empty( $source_ids ) ) {
+			// Attempt to fetch the original source data for Image B.
+			// For now, we pass null; the image pipeline will handle gracefully.
+			$source_data = null;
+		}
+
+		try {
+			$image_pipeline = new PRAutoBlogger_Image_Pipeline();
+			$result         = $image_pipeline->generate_and_attach_images( $post_id, $post_data, $source_data );
+
+			// Set Image A as the featured image.
+			if ( isset( $result['image_a_id'] ) ) {
+				set_post_thumbnail( $post_id, $result['image_a_id'] );
+				PRAutoBlogger_Logger::instance()->info(
+					sprintf( 'Set featured image (attachment %d) for post %d', $result['image_a_id'], $post_id ),
+					'publisher'
+				);
+			}
+
+			// Store Image B ID in post meta for A/B tracking.
+			if ( isset( $result['image_b_id'] ) ) {
+				update_post_meta( $post_id, '_prautoblogger_image_b_id', $result['image_b_id'] );
+				PRAutoBlogger_Logger::instance()->info(
+					sprintf( 'Stored Image B (attachment %d) in post meta for post %d', $result['image_b_id'], $post_id ),
+					'publisher'
+				);
+			}
+
+			// Log errors if any occurred (but don't let them block post creation).
+			if ( ! empty( $result['errors'] ) ) {
+				foreach ( $result['errors'] as $error ) {
+					PRAutoBlogger_Logger::instance()->warning(
+						'Image generation warning for post ' . $post_id . ': ' . $error,
+						'publisher'
+					);
+				}
+			}
+
+			// Log total cost.
+			if ( $result['cost_usd'] > 0.0 ) {
+				PRAutoBlogger_Logger::instance()->info(
+					sprintf( 'Image generation cost: $%.4f for post %d', $result['cost_usd'], $post_id ),
+					'publisher'
+				);
+			}
+		} catch ( \Exception $e ) {
+			// Log the error but don't re-throw — post is already created.
+			PRAutoBlogger_Logger::instance()->warning(
+				'Image pipeline exception for post ' . $post_id . ': ' . $e->getMessage(),
+				'publisher'
+			);
+		}
+	}
 }

tests/unit/Core/ImagePipelineTest.php

@@ -0,0 +1,149 @@
+<?php
+/**
+ * Tests for PRAutoBlogger_Image_Pipeline.
+ *
+ * Validates image generation orchestration, including A/B generation,
+ * cost tracking, and graceful failure handling.
+ *
+ * @package PRAutoBlogger\Tests\Core
+ */
+
+namespace PRAutoBlogger\Tests\Core;
+
+use PRAutoBlogger\Tests\BaseTestCase;
+use Brain\Monkey\Functions;
+
+class ImagePipelineTest extends BaseTestCase {
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		// Mock WordPress functions.
+		Functions\when( 'wp_generate_uuid4' )->returnArg();
+		Functions\when( 'get_option' )->alias( function ( $key, $default = false ) {
+			static $options = [
+				'prautoblogger_image_enabled'      => '1',
+				'prautoblogger_image_style_suffix' => 'Style: test style',
+			];
+			return $options[ $key ] ?? $default;
+		} );
+		Functions\when( 'sanitize_text_field' )->returnArg();
+		Functions\when( 'update_post_meta' )->justReturn( true );
+	}
+
+	/**
+	 * Test generate_and_attach_images() returns early if disabled.
+	 */
+	public function test_generate_and_attach_images_skipped_if_disabled(): void {
+		Functions\when( 'get_option' )->alias( function ( $key, $default = false ) {
+			static $options = [ 'prautoblogger_image_enabled' => '0' ];
+			return $options[ $key ] ?? $default;
+		} );
+
+		// Mock the logger.
+		$logger = $this->createMock( \PRAutoBlogger_Logger::class );
+		$logger->expects( $this->once() )->method( 'info' );
+
+		$provider       = $this->createMock( \PRAutoBlogger_Image_Provider_Interface::class );
+		$provider->expects( $this->never() )->method( 'generate_image' );
+		$cost_tracker   = $this->createMock( \PRAutoBlogger_Cost_Tracker::class );
+
+		$pipeline = new \PRAutoBlogger_Image_Pipeline( $provider, $cost_tracker );
+		$result   = $pipeline->generate_and_attach_images( 1, [ 'post_title' => 'Test' ] );
+
+		$this->assertArrayHasKey( 'cost_usd', $result );
+		$this->assertArrayHasKey( 'errors', $result );
+		$this->assertEmpty( $result['errors'] );
+	}
+
+	/**
+	 * Test generate_and_attach_images() returns cost and error array structure.
+	 */
+	public function test_generate_and_attach_images_returns_correct_structure(): void {
+		$provider = $this->createMock( \PRAutoBlogger_Image_Provider_Interface::class );
+		$provider->method( 'estimate_cost' )->willReturn( 0.05 );
+		$provider->method( 'generate_image' )->willReturn( [
+			'bytes'      => 'fake_image_data',
+			'mime_type'  => 'image/png',
+			'width'      => 1200,
+			'height'     => 630,
+			'model'      => 'flux-1-schnell',
+			'seed'       => 123,
+			'cost_usd'   => 0.05,
+			'latency_ms' => 2000,
+		] );
+
+		$cost_tracker = $this->createMock( \PRAutoBlogger_Cost_Tracker::class );
+		$cost_tracker->method( 'would_exceed_budget' )->willReturn( false );
+		$cost_tracker->method( 'log_image_generation' )->willReturn( true );
+
+		$pipeline = new \PRAutoBlogger_Image_Pipeline( $provider, $cost_tracker );
+
+		// Mock file writing for sideload.
+		Functions\when( 'get_temp_dir' )->justReturn( '/tmp/' );
+		Functions\when( 'media_handle_sideload' )->justReturn( 42 );
+
+		$result = $pipeline->generate_and_attach_images( 1, [ 'post_title' => 'Test' ] );
+
+		$this->assertArrayHasKey( 'cost_usd', $result );
+		$this->assertArrayHasKey( 'errors', $result );
+		$this->assertIsFloat( $result['cost_usd'] );
+		$this->assertIsArray( $result['errors'] );
+	}
+
+	/**
+	 * Test that cost is accumulated when both images are generated.
+	 */
+	public function test_cost_is_accumulated_for_both_images(): void {
+		$provider = $this->createMock( \PRAutoBlogger_Image_Provider_Interface::class );
+		$provider->method( 'estimate_cost' )->willReturn( 0.05 );
+		$provider->method( 'generate_image' )->willReturn( [
+			'bytes'      => 'fake_image_data',
+			'mime_type'  => 'image/png',
+			'width'      => 1200,
+			'height'     => 630,
+			'model'      => 'flux-1-schnell',
+			'cost_usd'   => 0.05,
+			'latency_ms' => 2000,
+		] );
+
+		$cost_tracker = $this->createMock( \PRAutoBlogger_Cost_Tracker::class );
+		$cost_tracker->method( 'would_exceed_budget' )->willReturn( false );
+		$cost_tracker->expects( $this->exactly( 2 ) )->method( 'log_image_generation' );
+
+		$pipeline = new \PRAutoBlogger_Image_Pipeline( $provider, $cost_tracker );
+
+		Functions\when( 'get_temp_dir' )->justReturn( '/tmp/' );
+		Functions\when( 'media_handle_sideload' )->justReturn( 42 );
+
+		$result = $pipeline->generate_and_attach_images(
+			1,
+			[ 'post_title' => 'Test' ],
+			[ 'title' => 'Source' ]
+		);
+
+		// Cost should be accumulated from both images.
+		$this->assertGreaterThan( 0.05, $result['cost_usd'] );
+	}
+
+	/**
+	 * Test graceful handling when image generation fails.
+	 */
+	public function test_graceful_failure_when_image_generation_fails(): void {
+		$provider = $this->createMock( \PRAutoBlogger_Image_Provider_Interface::class );
+		$provider->method( 'estimate_cost' )->willReturn( 0.05 );
+		$provider->method( 'generate_image' )->willThrowException( new \Exception( 'API timeout' ) );
+
+		$cost_tracker = $this->createMock( \PRAutoBlogger_Cost_Tracker::class );
+		$cost_tracker->method( 'would_exceed_budget' )->willReturn( false );
+
+		$pipeline = new \PRAutoBlogger_Image_Pipeline( $provider, $cost_tracker );
+
+		$result = $pipeline->generate_and_attach_images( 1, [ 'post_title' => 'Test' ] );
+
+		// Should record error but return valid structure.
+		$this->assertIsArray( $result );
+		$this->assertNotEmpty( $result['errors'] );
+		$this->assertStringContainsString( 'API timeout', implode( ' ', $result['errors'] ) );
+	}
+}

tests/unit/Core/ImagePromptBuilderTest.php

@@ -0,0 +1,122 @@
+<?php
+/**
+ * Tests for PRAutoBlogger_Image_Prompt_Builder.
+ *
+ * Validates prompt generation from article content and source data,
+ * including style suffix appending and HTML stripping.
+ *
+ * @package PRAutoBlogger\Tests\Core
+ */
+
+namespace PRAutoBlogger\Tests\Core;
+
+use PRAutoBlogger\Tests\BaseTestCase;
+use Brain\Monkey\Functions;
+
+class ImagePromptBuilderTest extends BaseTestCase {
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		// Mock WordPress functions.
+		Functions\when( 'wp_strip_all_tags' )->alias( function ( $str ) {
+			return wp_strip_all_tags( $str );
+		} );
+		Functions\when( 'sanitize_text_field' )->returnArg();
+		Functions\when( 'get_option' )->alias( function ( $key, $default = false ) {
+			static $options = [];
+			return $options[ $key ] ?? $default;
+		} );
+	}
+
+	/**
+	 * Test build_article_prompt() generates a prompt from article title and content.
+	 */
+	public function test_build_article_prompt_from_content(): void {
+		$builder = new \PRAutoBlogger_Image_Prompt_Builder();
+
+		$article_data = [
+			'post_title'   => 'How to Train Your Dragon',
+			'post_content' => '<p>Dragons are fascinating creatures. Learn the secrets.</p>',
+		];
+
+		$prompt = $builder->build_article_prompt( $article_data );
+
+		$this->assertStringContainsString( 'How to Train Your Dragon', $prompt );
+		$this->assertStringContainsString( 'Dragons are fascinating', $prompt );
+		// Style suffix should be appended.
+		$this->assertNotEmpty( $prompt );
+		$this->assertGreaterThan( 50, strlen( $prompt ) );
+	}
+
+	/**
+	 * Test build_article_prompt() handles missing content gracefully.
+	 */
+	public function test_build_article_prompt_with_missing_content(): void {
+		$builder = new \PRAutoBlogger_Image_Prompt_Builder();
+
+		$article_data = [
+			'post_title' => 'Minimal Article',
+		];
+
+		$prompt = $builder->build_article_prompt( $article_data );
+
+		$this->assertStringContainsString( 'Minimal Article', $prompt );
+		$this->assertNotEmpty( $prompt );
+	}
+
+	/**
+	 * Test build_source_prompt() generates a prompt from Reddit data.
+	 */
+	public function test_build_source_prompt_from_reddit_data(): void {
+		$builder = new \PRAutoBlogger_Image_Prompt_Builder();
+
+		$source_data = [
+			'title'    => 'Help: My Robot Won\'t Stop Dancing',
+			'comments' => [
+				'Have you tried unplugging it?',
+				'Maybe it\'s just happy.',
+			],
+		];
+
+		$prompt = $builder->build_source_prompt( $source_data );
+
+		$this->assertStringContainsString( 'Robot', $prompt );
+		$this->assertStringContainsString( 'Dancing', $prompt );
+		$this->assertNotEmpty( $prompt );
+	}
+
+	/**
+	 * Test build_source_prompt() handles missing comments.
+	 */
+	public function test_build_source_prompt_without_comments(): void {
+		$builder = new \PRAutoBlogger_Image_Prompt_Builder();
+
+		$source_data = [
+			'title' => 'Standalone Title',
+		];
+
+		$prompt = $builder->build_source_prompt( $source_data );
+
+		$this->assertStringContainsString( 'Standalone Title', $prompt );
+		$this->assertNotEmpty( $prompt );
+	}
+
+	/**
+	 * Test that prompts don't exceed reasonable length.
+	 */
+	public function test_prompts_are_reasonably_sized(): void {
+		$builder = new \PRAutoBlogger_Image_Prompt_Builder();
+
+		$long_content = '<p>' . str_repeat( 'a', 5000 ) . '</p>';
+		$article_data = [
+			'post_title'   => 'Test',
+			'post_content' => $long_content,
+		];
+
+		$prompt = $builder->build_article_prompt( $article_data );
+
+		// Prompt should be under 500 chars (concept + style suffix).
+		$this->assertLessThan( 500, strlen( $prompt ) );
+	}
+}