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

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)

• Navigate to gemini.google.com

• Click "ツール" (Tools) button

• Select "画像を作成" (Create Image) - Activates NanoBanana

• Enter prompt and generate

• Download generated image

Reference Image Mode (参考画像あり) - NEW!

• Upload reference image to Gemini

• AI analyzes visual elements (style, colors, lighting, etc.)

• Extract analysis as YAML format

• Generate optimized meta-prompt

• 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)

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!

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

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)

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