Agent skill

gemini-image-generator

Generate images using Google Gemini NanoBanana via browser automation. Use this skill for general-purpose AI image generation from text prompts. Includes persistent authentication, automatic environment setup, and reference image support for style matching.

View SKILL.md on GitHub Repository
Stars 163
Forks 31

Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/nanobanana-pro

SKILL.md

Gemini Image Generator

Gemini NanoBananaを使った汎用AI画像生成スキル。

When to Use This Skill

Trigger when user:

  • Asks to generate/create images with AI
  • Mentions "Gemini image", "generate picture", "create artwork"
  • Requests visual content from text descriptions
  • Wants to produce illustrations or graphics
  • Wants to create images matching a reference image's style (NEW!)

For specific use cases, use specialized skills:

  • LP/セールスレター画像 → gemini-lp-generator
  • ウェビナースライド → gemini-slide-generator

Quick Start

bash
cd /path/to/gemini-image-generator

# 1. Check authentication
python scripts/run.py auth_manager.py status

# 2. Authenticate (if needed)
python scripts/run.py auth_manager.py setup

# 3. Generate image (basic)
python scripts/run.py image_generator.py \
  --prompt "sunset over mountains, watercolor style" \
  --output output/my_image.png

# 4. Generate with reference image (NEW!)
python scripts/run.py image_generator.py \
  --prompt "犬を描いて" \
  --reference-image "/path/to/reference.png" \
  --output output/styled_dog.png

How It Works

Basic Mode (テキストのみ)

  1. Navigate to gemini.google.com
  2. Click "ツール" (Tools) button
  3. Select "画像を作成" (Create Image) - Activates NanoBanana
  4. Enter prompt and generate
  5. Download generated image

Reference Image Mode (参考画像あり) - NEW!

  1. Upload reference image to Gemini
  2. AI analyzes visual elements (style, colors, lighting, etc.)
  3. Extract analysis as YAML format
  4. Generate optimized meta-prompt
  5. Create new image with matching style
┌────────────────┐     ┌────────────────┐     ┌────────────────┐
│  📷 Reference  │ →   │  📋 YAML       │ →   │  📝 Optimized  │
│     Image      │     │    Analysis    │     │     Prompt     │
└────────────────┘     └────────────────┘     └────────────────┘
                                                      │
                                                      ▼
                                              ┌────────────────┐
                                              │  🖼️ Generated  │
                                              │     Image      │
                                              └────────────────┘

Parameters

Parameter Required Default Description
--prompt Yes - Image generation prompt
--output No output/generated_image.png Output file path
--reference-image No - Reference image for style extraction
--yaml-output No - Save YAML analysis to file
--show-browser No False Show browser for debugging
--timeout No 180 Max wait time in seconds

Prompt Examples

Basic Examples (テキストのみ)

bash
# Landscape
python scripts/run.py image_generator.py \
  --prompt "serene sunset over snow-capped mountains, warm orange sky, photorealistic"

# Art style
python scripts/run.py image_generator.py \
  --prompt "watercolor painting of a cat sitting by window, soft colors"

# Product photo
python scripts/run.py image_generator.py \
  --prompt "professional product photography, white background, soft lighting"

Reference Image Examples (参考画像あり) - NEW!

bash
# Match style of reference image
python scripts/run.py image_generator.py \
  --prompt "犬を描いて" \
  --reference-image "examples/watercolor_cat.png" \
  --output output/watercolor_dog.png

# Save YAML analysis for review
python scripts/run.py image_generator.py \
  --prompt "森の風景" \
  --reference-image "examples/sunset.jpg" \
  --yaml-output output/analysis.yaml \
  --output output/forest.png

# Debug mode with browser visible
python scripts/run.py image_generator.py \
  --prompt "カフェの内装" \
  --reference-image "examples/cozy_room.png" \
  --show-browser \
  --output output/cafe.png

Standalone Tools

bash
# Extract YAML only (without generating image)
python scripts/run.py prompt_extractor.py \
  --image "examples/reference.png" \
  --output analysis.yaml

# Generate prompt from YAML
python scripts/run.py meta_prompt.py \
  --yaml analysis.yaml \
  --request "猫を描いて"

Authentication

This skill manages browser authentication for all Gemini-based skills:

  • gemini-slide-generator (shares browser profile)
  • gemini-lp-generator (shares browser profile)
bash
# Check status
python scripts/run.py auth_manager.py status

# Setup (opens browser for Google login)
python scripts/run.py auth_manager.py setup

# Clear session
python scripts/run.py auth_manager.py clear

Troubleshooting

Problem Solution
Not authenticated Run auth_manager.py setup
Timeout Increase with --timeout 300
UI not found Use --show-browser to debug
Generation refused Modify prompt (avoid restricted content)

Data Storage

  • data/browser_profile/ - Browser session (shared with other Gemini skills)
  • data/state.json - Authentication state
  • output/ - Generated images

Architecture

scripts/
├── config.py           # Centralized settings
├── browser_utils.py    # BrowserFactory and StealthUtils
├── auth_manager.py     # Authentication management
├── image_generator.py  # Image generation (with reference image support)
├── prompt_extractor.py # Extract visual elements as YAML (NEW!)
├── meta_prompt.py      # Generate optimized prompts from YAML (NEW!)
└── run.py              # Wrapper script for venv

docs/
└── UPGRADE_SPEC.md     # Feature specification with diagrams

Notes

  • First generation takes longer (browser startup)
  • Subsequent generations faster (session reuse)
  • Authentication persists ~7 days
  • UI selectors may break when Gemini updates

Didn't find tool you were looking for?

Be as detailed as possible for better results