kkoppenhaver

nano-banana

46
3
# Install this skill:
npx skills add kkoppenhaver/cc-nano-banana

Or install specific skill: npx add-skill https://github.com/kkoppenhaver/cc-nano-banana

# Description

REQUIRED for all image generation requests. Generate and edit images using Nano Banana (Gemini CLI). Handles blog featured images, YouTube thumbnails, icons, diagrams, patterns, illustrations, photos, visual assets, graphics, artwork, pictures. Use this skill whenever the user asks to create, generate, make, draw, design, or edit any image or visual content.

# SKILL.md


name: nano-banana
description: REQUIRED for all image generation requests. Generate and edit images using Nano Banana (Gemini CLI). Handles blog featured images, YouTube thumbnails, icons, diagrams, patterns, illustrations, photos, visual assets, graphics, artwork, pictures. Use this skill whenever the user asks to create, generate, make, draw, design, or edit any image or visual content.
allowed-tools: Bash(gemini:*)


Nano Banana Image Generation

Generate professional images via the Gemini CLI's nanobanana extension.

When to Use This Skill

ALWAYS use this skill when the user:
- Asks for any image, graphic, illustration, or visual
- Wants a thumbnail, featured image, or banner
- Requests icons, diagrams, or patterns
- Asks to edit, modify, or restore a photo
- Uses words like: generate, create, make, draw, design, visualize

Do NOT attempt to generate images through any other method.

Before First Use

  1. Verify extension is installed:
    bash gemini extensions list | grep nanobanana
  2. If missing, install it:
    bash gemini extensions install https://github.com/gemini-cli-extensions/nanobanana
  3. Verify API key is set:
    bash [ -n "$GEMINI_API_KEY" ] && echo "API key configured" || echo "Missing GEMINI_API_KEY"

Command Selection

User Request Command
"make me a blog header" /generate
"create an app icon" /icon
"draw a flowchart of..." /diagram
"fix this old photo" /restore
"remove the background" /edit
"create a repeating texture" /pattern
"make a comic strip" /story

Available Commands

Note: Always use the --yolo flag to automatically approve all tool actions.

Command Use Case
gemini --yolo "/generate 'prompt'" Text-to-image generation
gemini --yolo "/edit file.png 'instruction'" Modify existing image
gemini --yolo "/restore old_photo.jpg 'fix scratches'" Repair damaged photos
gemini --yolo "/icon 'description'" App icons, favicons, UI elements
gemini --yolo "/diagram 'description'" Flowcharts, architecture diagrams
gemini --yolo "/pattern 'description'" Seamless textures and patterns
gemini --yolo "/story 'description'" Sequential/narrative images
gemini --yolo "/nanobanana prompt" Natural language interface

Common Options

  • --yolo - Required. Auto-approve all tool actions (no confirmation prompts)
  • --count=N - Generate N variations (1-8)
  • --preview - Auto-open generated images
  • --styles="style1,style2" - Apply artistic styles
  • --format=grid|separate - Output arrangement

Common Sizes

Use Case Dimensions Notes
YouTube thumbnail 1280x720 --aspect=16:9
Blog featured image 1200x630 Social preview friendly
Square social 1080x1080 Instagram, LinkedIn
Twitter/X header 1500x500 Wide banner
Vertical story 1080x1920 --aspect=9:16

Model Selection

Default: gemini-2.5-flash-image (~$0.04/image)

For higher quality (4K, better reasoning):

export NANOBANANA_MODEL=gemini-3-pro-image-preview
# Modern illustration style
gemini --yolo "/generate 'modern flat illustration of developer coding at laptop, purple and blue gradient background, minimalist style, no text' --preview"

# Professional photography style
gemini --yolo "/generate 'professional editorial photo of coffee cup next to laptop on wooden desk, morning sunlight, shallow depth of field, no text' --count=3"

# Tech/abstract
gemini --yolo "/generate 'abstract visualization of neural network connections, dark background with glowing blue nodes, futuristic style' --preview"

Icon Generation

gemini --yolo "/icon 'minimalist app logo for productivity tool' --sizes='64,128,256,512' --type='app-icon' --corners='rounded'"

Diagram Generation

gemini --yolo "/diagram 'user authentication flow with OAuth' --type='flowchart' --style='modern'"

Output Location

All generated images are saved to ./nanobanana-output/ in the current directory.

Presenting Results

After generation completes:
1. List contents of ./nanobanana-output/ to find generated files
2. Present the most recent image(s) to the user
3. Offer to regenerate with variations if needed

Refinements and Iterations

When the user asks for changes:
- "Try again" / "Give me options": Regenerate with --count=3
- "Make it more [adjective]": Adjust prompt and regenerate
- "Edit this one": Use gemini --yolo "/edit nanobanana-output/filename.png 'adjustment'"
- "Different style": Add --styles="requested_style" to the command

Prompt Tips

  1. Be specific: Include style, mood, colors, composition details
  2. Add "no text": If you don't want text rendered in the image
  3. Reference styles: "editorial photography", "flat illustration", "3D render", "watercolor"
  4. Specify aspect ratio context: "wide banner", "square thumbnail", "vertical story"

Troubleshooting

Problem Solution
GEMINI_API_KEY not set export GEMINI_API_KEY="your-key"
Extension not found Run install command from setup section
Quota exceeded Wait for reset or switch to flash model
Image generation failed Check prompt for policy violations, simplify request
Output directory missing Will be created automatically on first run

# README.md

Nano Banana

A Claude Code skill for generating and editing images using the Gemini CLI's nanobanana extension.

Features

  • Text-to-image generation - Create images from natural language prompts
  • Image editing - Modify existing images with instructions
  • Photo restoration - Repair damaged or old photos
  • Icon generation - Create app icons and favicons
  • Diagram creation - Generate flowcharts and architecture diagrams
  • Pattern generation - Create seamless textures and patterns
  • Story/sequential images - Generate narrative image sequences

Prerequisites

  1. Gemini CLI - Install from gemini-cli
  2. Gemini API Key - Get one from Google AI Studio
  3. nanobanana extension - Installed via Gemini CLI

Installation

1. Install the Gemini CLI

npm install -g @anthropic-ai/gemini-cli

2. Set your API key

export GEMINI_API_KEY="your-api-key"

3. Install the nanobanana extension

gemini extensions install https://github.com/gemini-cli-extensions/nanobanana

4. Install this skill

Copy the SKILL.md file to your Claude Code skills directory:

mkdir -p ~/.claude/skills/nano-banana
cp SKILL.md ~/.claude/skills/nano-banana/

Or clone this repository directly:

git clone https://github.com/kkoppenhaver/cc-nano-banana ~/.claude/skills/nano-banana

Usage

Once installed, Claude Code will automatically use this skill when you ask for image generation. Examples:

  • "Generate a blog header image for a post about machine learning"
  • "Create a YouTube thumbnail for a coding tutorial"
  • "Make an app icon for a productivity tool"
  • "Draw a flowchart showing user authentication"
  • "Edit this image to remove the background"

Available Commands

Command Description
/generate Text-to-image generation
/edit Modify existing images
/restore Repair damaged photos
/icon Generate app icons
/diagram Create flowcharts and diagrams
/pattern Generate seamless patterns
/story Create sequential/narrative images
/nanobanana Natural language interface

Common Options

Option Description
--yolo Auto-approve tool actions (no prompts)
--count=N Generate N variations (1-8)
--preview Auto-open generated images
--styles="style1,style2" Apply artistic styles
--format=grid\|separate Output arrangement

Output

Generated images are saved to ./nanobanana-output/ in your current working directory.

Model Selection

Default model: gemini-2.5-flash-image (~$0.04/image)

For higher quality output:

export NANOBANANA_MODEL=gemini-3-pro-image-preview

License

MIT

Contributing

Contributions are welcome! Please open an issue or submit a pull request.

# Supported AI Coding Agents

This skill is compatible with the SKILL.md standard and works with all major AI coding agents:

Learn more about the SKILL.md standard and how to use these skills with your preferred AI coding agent.