nano-banana

Original：🇺🇸 English

Translated

Generates AI images using the nano-banana CLI (Gemini 3.1 Flash default, Pro available). Handles multi-resolution (512-4K), aspect ratios, reference images for style transfer, green screen workflow for transparent assets, cost tracking, and exact dimension control. Use when asked to "generate an image", "create a sprite", "make an asset", "generate artwork", or any image generation task for UI mockups, game assets, videos, or marketing materials.

2installs

Sourcekingbootoshi/nano-banana-2-skill

Added on2026-03-04

NPX Install

npx skill4agent add kingbootoshi/nano-banana-2-skill nano-banana

SKILL.md Content

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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

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

# 3. Link globally (creates `nano-banana` command via Bun - no sudo)
cd ~/tools/nano-banana-2 && bun link

# 4. Set up API key
mkdir -p ~/.nano-banana
echo "GEMINI_API_KEY=<ask user for their key>" > ~/.nano-banana/.env

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:

bash

mkdir -p ~/.local/bin
ln -sf ~/tools/nano-banana-2/src/cli.ts ~/.local/bin/nano-banana
# Then ensure ~/.local/bin is on PATH:
echo 'export PATH="$HOME/.local/bin:$PATH"' >> ~/.zshrc
source ~/.zshrc

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

Option	Default	Description
`-o, --output`	`nano-gen-{timestamp}`	Output filename (no extension)
`-s, --size`	`1K`	Image size: `512` , `1K` , `2K` , or `4K`
`-a, --aspect`	model default	Aspect ratio: `1:1` , `16:9` , `9:16` , `4:3` , `3:4` , etc.
`-m, --model`	`flash`	Model: `flash` / `nb2` , `pro` / `nb-pro` , or any model ID
`-d, --dir`	current directory	Output directory
`-r, --ref`	-	Reference image (can use multiple times)
`-t, --transparent`	-	Generate on green screen, remove background (FFmpeg)
`--api-key`	-	Gemini API key (overrides env/file)
`--costs`	-	Show cost summary

Models

Alias	Model	Use When
`flash` , `nb2`	Gemini 3.1 Flash	Default. Fast, cheap (~$0.067/1K image)
`pro` , `nb-pro`	Gemini 3 Pro	Highest quality needed (~$0.134/1K image)

Sizes

Size	Cost (Flash)	Cost (Pro)
`512`	~$0.045	Flash only
`1K`	~$0.067	~$0.134
`2K`	~$0.101	~$0.201
`4K`	~$0.151	~$0.302

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

bash

nano-banana "minimal dashboard UI with dark theme"
nano-banana "cinematic landscape" -s 2K -a 16:9
nano-banana "quick concept sketch" -s 512

Model Selection

bash

# Default (Flash - fast, cheap)
nano-banana "your prompt"

# Pro (highest quality)
nano-banana "detailed portrait" --model pro -s 2K

Reference Images (Style Transfer / Editing)

bash

# Edit existing image
nano-banana "change the background to pure white" -r dark-ui.png -o light-ui

# Style transfer - multiple references
nano-banana "combine these two styles" -r style1.png -r style2.png -o combined

Transparent Assets

bash

nano-banana "robot mascot character" -t -o mascot
nano-banana "pixel art treasure chest" -t -o chest

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:

First
```
-r
```
flag: your reference/style image
Last
```
-r
```
flag: blank image in target dimensions
Include dimensions in prompt

bash

nano-banana "pixel art character in style of first image, 256x256" -r style.png -r blank-256x256.png -o sprite

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:

bash

nano-banana --costs

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

bash

# UI mockups
nano-banana "clean SaaS dashboard with analytics charts, white background"

# Widescreen cinematic
nano-banana "cyberpunk cityscape at sunset" -a 16:9 -s 2K

# Product shots with Pro quality
nano-banana "premium software product hero image" --model pro

# Quick low-res concept
nano-banana "rough sketch of a robot" -s 512

# Dark mode UI
nano-banana "Premium SaaS chat interface, dark mode, minimal, Linear-style aesthetic"

# Game assets with transparency (green screen auto-prompted)
nano-banana "pixel art treasure chest" -t -o chest

# Portrait aspect ratio
nano-banana "mobile app onboarding screen" -a 9:16

API Key Setup

The CLI resolves the Gemini API key in this order:

```
--api-key
```
flag
```
GEMINI_API_KEY
```
environment variable
```
.env
```
file in current directory
```
.env
```
file next to the CLI script
```
~/.nano-banana/.env
```

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

nano-banana

NPX Install

Tags

SKILL.md Content

nano-banana

/init - First-Time Setup

Quick Reference

Core Options

Models

Sizes

Aspect Ratios

Key Workflows

Basic Generation

Model Selection

Reference Images (Style Transfer / Editing)

Transparent Assets

Exact Dimensions

Reference Order Matters

Cost Tracking

Use Cases

Prompt Examples

API Key Setup