nano-banana

nano-banana

AI image generation CLI. Default model: Gemini 3.1 Flash Image Preview (Nano Banana 2).

/init - First-Time Setup

When the user says "init", "setup nano-banana", or "install nano-banana", run these commands to get the CLI tool on their machine. No sudo required.

Prerequisites: Bun must be installed. If not: curl -fsSL https://bun.sh/install | bash

# 1. Clone the repo
git clone https://github.com/kingbootoshi/nano-banana-2-skill.git ~/tools/nano-banana-2
 
# 2. Install dependencies
cd ~/tools/nano-banana-2 && bun install

After init, the user can type nano-banana "prompt" from anywhere.

If bun link fails or the command is not found after linking, fall back to:

Get a Gemini API key at: https://aistudio.google.com/apikey

Quick Reference

• Command: nano-banana "prompt" [options]
• Default: 1K resolution, Flash model, current directory

Core Options

Models

Sizes

Aspect Ratios

Supported: 1:1, 16:9, 9:16, 4:3, 3:4, 3:2, 2:3, 4:5, 5:4, 21:9

Use -a flag: nano-banana "cinematic scene" -a 16:9

Key Workflows

Basic Generation

Model Selection

Reference Images (Style Transfer / Editing)

Transparent Assets

The -t flag automatically prompts the AI to generate on a green screen, then uses FFmpeg colorkey + despill to key out the background and remove green spill from edge pixels. Pixel-perfect transparency with no manual prompting needed.

Requires: brew install ffmpeg imagemagick

Exact Dimensions

To get a specific output dimension:

1. First -r flag: your reference/style image
2. Last -r flag: blank image in target dimensions
3. Include dimensions in prompt

Reference Order Matters

• First reference: primary style/content source
• Additional references: secondary influences
• Last reference: controls output dimensions (if using blank image trick)

Cost Tracking

Every generation is logged to ~/.nano-banana/costs.json. View summary:

Use Cases

• Landing page assets - product mockups, UI previews
• Image editing - transform existing images with prompts
• Style transfer - combine multiple reference images
• Marketing materials - hero images, feature illustrations
• UI iterations - quickly generate variations of designs
• Transparent assets - icons, logos, mascots with no background
• Game assets - sprites, backgrounds, characters
• Video production - visual elements for video compositions

Prompt Examples

API Key Setup

The CLI resolves the Gemini API key in this order:

1. --api-key flag
2. GEMINI_API_KEY environment variable
3. .env file in current directory
4. .env file next to the CLI script
5. ~/.nano-banana/.env

Get a key at: https://aistudio.google.com/apikey