Image Generation

Image Generation Skill

Generate professional AI images using Google Gemini via the bundled CLI script.

When to Invoke This Skill

Invoke immediately when:

Web Development

• Hero sections without images
• Feature illustrations needed
• Placeholder images in code (placeholder.jpg, stock-photo.png)
• Empty visual sections (<section class="hero"> without images)
• Landing pages and marketing sites

Presentations & Documents

• Cover images and headers
• Conceptual diagrams
• Section dividers

Applications

• Onboarding illustrations
• Empty state graphics
• Error page visuals

Using the CLI

Run the bundled CLI script via bash:

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node "${CLAUDE_PLUGIN_ROOT}/mcp-server/build/cli.bundle.js" \
  --prompt "Your detailed image description" \
  --output "./path/to/output.png" \
  --aspect-ratio "16:9"

Parameters

Environment Variables

Output

The CLI outputs JSON:

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{"success": true, "filePath": "/path/to/generated-image.png"}

Or on error:

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{"success": false, "error": "Error message"}

Aspect Ratio Selection

• 16:9 - Hero images, website headers, presentations
• 1:1 - Social media, thumbnails, profile images
• 9:16 - Mobile stories, vertical banners
• 4:3 - Blog posts, general web content
• 3:2 - Photography-style images

Prompt Crafting

Use this formula for effective prompts:

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[Style] [Subject] [Composition] [Context/Atmosphere]

Examples

Hero Image for Tech Startup

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Minimalist 3D illustration of abstract geometric shapes floating in space,
soft gradient background from deep purple to electric blue, subtle glow effects,
modern professional aesthetic, wide composition for website header

E-commerce Product

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Clean product photography of modern wireless headphones on white marble surface,
soft studio lighting from left, subtle shadows, high-end minimalist aesthetic,
centered composition

Blog Post Header

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Aerial photography of winding river through autumn forest, golden hour lighting,
warm color palette with oranges and reds, cinematic wide shot, serene atmosphere

App Illustration

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Flat vector illustration of person organizing digital files on floating screens,
soft pastel colors, isometric perspective, clean lines, friendly approachable style

Pattern Detection

Automatically invoke this skill when you see:

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<!-- Placeholder detection -->
<img src="placeholder.jpg" alt="Hero">
<!-- Action: Invoke skill and generate a custom hero image -->

<!-- Empty visual section -->
<section class="features">
  <h2>Our Features</h2>
  <!-- No images -->
</section>
<!-- Action: Invoke skill to create feature illustrations -->

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/* Generic stock reference */
.banner { background: url('stock-image.jpg'); }
/* Action: Invoke skill to create a unique background */

Workflow

1. Detect Need - Identify visual content requirements (hero, illustrations, backgrounds)
2. Invoke Skill - Use the Skill tool with skill: "image-generation" immediately
3. Analyze Context - Understand project style and brand
4. Craft Prompt - Build detailed prompt using the formula above
5. Generate - Run the CLI script with optimized parameters
6. Integrate - Place image in project with proper references

Model Selection

The CLI is dual-provider: the --model value routes the request — model names starting with gpt-image or dall-e go to OpenAI, everything else goes to Gemini. When --model is omitted, IMAGE_PROVIDER picks which provider's default model is used.

• Gemini (GEMINI_DEFAULT_MODEL, e.g. gemini-3-pro-image) — models are fetched dynamically from the Gemini API; the CLI falls back to the first discovered image-capable model if no default is set. Prefer Gemini for iterative creative work and when relying on the dynamically discovered model catalog.
• OpenAI (OPENAI_DEFAULT_MODEL, default gpt-image-2) — use when you specifically need OpenAI's gpt-image-2 model, or when only an OpenAI API key is configured. Note OpenAI's image sizes are limited to 1024x1024/1536x1024/1024x1536; non-matching aspect ratios are mapped to the nearest supported size with a warning.

Best Practices

DO:

• Include specific style keywords
• Match aspect ratio to intended use
• Describe mood and atmosphere
• Specify color palette for brand consistency

DON'T:

• Use vague prompts ("make it look good")
• Ignore where the image will be used
• Skip aspect ratio for specific layouts

Reference

For advanced prompt techniques: references/prompt-crafting.md

Alternative: MCP Tool

If the MCP server is configured, you can also use:

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mcp__media-pipeline__create_asset

Parameters: prompt, outputPath, aspectRatio, model (routes to Gemini or OpenAI by name), referenceImages (up to 5 absolute paths, PNG/JPEG/WebP), mask, background, outputFormat (the last three are OpenAI-only)