Nanobanana Image Generation Skill

Generate or edit images using Google Gemini API through the nanobanana tool.

Requirements

• GEMINI_API_KEY: Must be configured in ~/.nanobanana.env or export GEMINI_API_KEY=<your-api-key>

• Python3 with depedent packages installed: google-genai, Pillow, python-dotenv. They could be installed via python3 -m pip install -r ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/requirements.txt if not installed yet.

• Executable: ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py

Instructions

For image generation

Ask the user for:

• What they want to create (the prompt)

• Desired aspect ratio/size (optional, defaults to 9:16 portrait)

• Output filename (optional, auto-generates UUID if not specified)

• Model preference (optional, defaults to gemini-3-pro-image-preview)

• Resolution (optional, defaults to 1K)

Run the nanobanana script with appropriate parameters:

python3 ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py --prompt "description of image" --output "filename.png"

Show the user the saved image path when complete

For image editing

Ask the user for:

• Input image file(s) to edit

• What changes they want (the prompt)

• Output filename (optional)

Run with input images:

python3 ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py --prompt "editing instructions" --input image1.png image2.png --output "edited.png"

Available Options

Aspect Ratios (--size)

• 1024x1024 (1:1) - Square

• 832x1248 (2:3) - Portrait

• 1248x832 (3:2) - Landscape

• 864x1184 (3:4) - Portrait

• 1184x864 (4:3) - Landscape

• 896x1152 (4:5) - Portrait

• 1152x896 (5:4) - Landscape

• 768x1344 (9:16) - Portrait (default)

• 1344x768 (16:9) - Landscape

• 1536x672 (21:9) - Ultra-wide

Models (--model)

• gemini-3-pro-image-preview (default) - Higher quality

• gemini-2.5-flash-image

• Faster generation

Resolution (--resolution)

• 1K (default)

• 2K

• 4K

Examples

Generate a simple image

python3 ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py --prompt "A serene mountain landscape at sunset with a lake"

Generate with specific size and output

python3 ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py
--prompt "Modern minimalist logo for a tech startup"
--size 1024x1024
--output "logo.png"

Generate landscape image with high resolution

python3 ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py
--prompt "Futuristic cityscape with flying cars"
--size 1344x768
--resolution 2K
--output "cityscape.png"

Edit existing images

python3 ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py
--prompt "Add a rainbow in the sky"
--input photo.png
--output "photo-with-rainbow.png"

Use faster model

python3 ${CLAUDE_PLUGIN_ROOT}/skills/nanobanana-skill/nanobanana.py
--prompt "Quick sketch of a cat"
--model gemini-2.5-flash-image
--output "cat-sketch.png"

Error Handling

If the script fails:

• Check that GEMINI_API_KEY is exported or set in ~/.nanobanana.env

• Verify input image files exist and are readable

• Ensure the output directory is writable

• If no image is generated, try making the prompt more specific about wanting an image

Best Practices

• Be descriptive in prompts - include style, mood, colors, composition

• For logos/graphics, use square aspect ratio (1024x1024)

• For social media posts, use 9:16 for stories or 1:1 for posts

• For wallpapers, use 16:9 or 21:9

• Start with 1K resolution for testing, upgrade to 2K/4K for final output

• Use gemini-3-pro-image-preview for best quality, gemini-2.5-flash-image for speed