gh-krishagel-geoffrey/skills/image-gen/SKILL.md

name, description, triggers, allowed-tools, version

name	description	triggers	allowed-tools	version
image-gen	Generate images using Google's Nano Banana Pro (Gemini 3 Pro Image) with workflow-based prompting	create image generate image make infographic create infographic generate diagram make diagram design visual create visual	Read, Write, Bash	0.1.0

Image Generation Skill

Generate professional images, infographics, and diagrams using Google's Nano Banana Pro model (gemini-3-pro-image-preview).

Model Capabilities

Nano Banana Pro (released November 20, 2025):

• Text rendering - Accurate, legible text in images
• Google Search grounding - Real-time data (weather, stocks, etc.)
• Multi-turn conversation - Iterative refinement
• Up to 14 reference images - For composition and style transfer
• Resolutions: 1K, 2K, 4K
• Aspect ratios: 1:1, 2:3, 3:2, 4:3, 16:9, 21:9

Scripts

All scripts use Python via uv run with inline dependencies.

generate.py - Text to Image

uv run scripts/generate.py "prompt" output.png [aspect_ratio] [size]

Examples:

# Basic image
uv run scripts/generate.py "A cozy coffee shop in autumn" coffee.png

# Infographic with specific aspect ratio
uv run scripts/generate.py "Infographic explaining how neural networks work" nn.png 16:9 2K

# 4K professional image
uv run scripts/generate.py "Professional headshot, studio lighting" headshot.png 3:2 4K

edit.py - Image Editing

uv run scripts/edit.py input.png "edit instructions" output.png

Examples:

# Edit existing image
uv run scripts/edit.py photo.png "Change the background to a beach sunset" edited.png

compose.py - Multi-Image Composition

uv run scripts/compose.py "prompt" output.png --refs image1.png image2.png

Examples:

# Combine styles from multiple images
uv run scripts/compose.py "Combine these styles into a logo" logo.png --refs style1.png style2.png

Workflows

Workflows provide structured approaches for specific visual types. Each workflow follows the PAI 6-step editorial process:

1. Extract narrative - Understand the complete story/concept
2. Derive visual concept - Single metaphor with 2-3 physical objects
3. Apply aesthetic - Define style, colors, mood
4. Construct prompt - Build detailed generation instructions
5. Generate - Execute via script
6. Validate - Check against criteria, regenerate if needed

Available Workflows

• infographic.md - Data visualization, statistics, explainers
• diagram.md - Technical diagrams, flowcharts, architecture

Workflow Usage

When generating images, follow the appropriate workflow:

For Infographics

1. What data/concept needs visualization?
2. What's the key insight or takeaway?
3. Aspect ratio: 16:9 (landscape) recommended
4. Include: clear hierarchy, minimal text, supporting icons
5. Generate at 2K minimum for text clarity

For Diagrams

1. What system/process is being illustrated?
2. What are the key components and relationships?
3. Style: flat colors, clean lines, minimal detail
4. Generate at 2K for label clarity

Environment Setup

Requires GEMINI_API_KEY environment variable. This should be set from Geoffrey's secrets:

source ~/Library/Mobile\ Documents/com~apple~CloudDocs/Geoffrey/secrets/.env

Best Practices

Infographics

• Use simple, direct prompts: "Infographic explaining how X works"
• Model auto-includes relevant icons/logos
• 16:9 aspect ratio works best
• Generate at 2K+ for readable text

General

• Multi-turn refinement: generate, then ask for specific changes
• Reference images improve consistency
• Be specific about style, mood, lighting
• SynthID watermark is automatic (Google provenance)

Output Location

By default, save images to /tmp/ or user-specified paths. For persistent storage, use:

~/Library/Mobile Documents/com~apple~CloudDocs/Geoffrey/images/

Limitations

• No photorealistic humans (safety filter)
• No copyrighted characters
• Maximum 14 reference images for composition
• 4K only available with Nano Banana Pro

Pricing

Size	Cost per Image
1K	Free tier / $0.04
2K	$0.134
4K	$0.24