Nano Banana Image Generator

Generate AI images styled with the Nano Banana Pro visual identity using Google Gemini API.

Key Features

• Nano Banana Pro Style: Auto-applies signature dark navy, golden yellow, teal color palette
• Multi-Key Support: Manage multiple Gemini API keys
• Round-Robin Rotation: Automatically rotates keys to distribute API usage
• Multiple Aspect Ratios: 1:1, 16:9, 9:16, 4:3, 3:4

Quick Start

# Generate an image
python scripts/generate_image.py "a futuristic productivity device" output.png

# With aspect ratio
python scripts/generate_image.py "app icon with lightning bolt" icon.png --aspect 1:1

API Key Management

Keys are stored in ~/.config/nano-banana-image/config.json and used in round-robin order.

List Keys

python scripts/generate_image.py keys list

Output:

Configured API Keys (2) - Round Robin Mode:
--------------------------------------------------
  1. default: AIzaSyDu8m...4Z0I [LAST USED]
  2. secondary: AIzaSyAxUw...ydqk [NEXT]
--------------------------------------------------
Strategy: Round-robin (auto-rotate on each call)

Add a Key

python scripts/generate_image.py keys add <name> <api-key>

# Examples:
python scripts/generate_image.py keys add default AIzaSy...
python scripts/generate_image.py keys add work AIzaSy...

Remove a Key

python scripts/generate_image.py keys remove <name>

Reset Rotation

python scripts/generate_image.py keys reset

Restarts round-robin from the first key.

First-Time Setup

On first use with no keys configured:

python scripts/generate_image.py --check

This shows setup instructions. User provides key, then:

python scripts/generate_image.py keys add default "AIzaSy..."

Image Generation

Usage

python scripts/generate_image.py "<description>" [output_path] [options]

Argument	Description	Default
description	What to generate (required)	-
output_path	Output file path	output.png
--aspect	Aspect ratio: 1:1, 16:9, 9:16, 4:3, 3:4	16:9
--model	Gemini model to use	gemini-3-pro-image-preview
--key	Use specific key (skips rotation)	next in rotation

Use Specific Key

# Use 'work' key for this generation only (doesn't affect rotation)
python scripts/generate_image.py "prompt" output.png --key work

Style Applied

All generated images automatically include Nano Banana Pro styling:

• Colors: Deep navy (#1C2833), golden yellow (#F4C430), teal (#00D9C0)
• Mood: Professional, tech-forward, premium, innovative
• Aesthetic: Dark mode, geometric shapes, high contrast, minimalist

Examples

Product Visualization

python scripts/generate_image.py "a compact smart device with glowing edges" product.png

Abstract Background

python scripts/generate_image.py "abstract geometric pattern with flowing particles" bg.png --aspect 16:9

Icon/Logo

python scripts/generate_image.py "minimalist sync icon with two rotating arrows" icon.png --aspect 1:1

Hero Image

python scripts/generate_image.py "futuristic AI brain with neural connections" hero.png

Prompt Tips

For best results, describe:

1. Subject: What is the main focus
2. Context: Environment or setting
3. Mood: Energy level, feeling
4. Details: Specific elements to include

The Nano Banana style (colors, aesthetic) is automatically added.

Good prompts:

• "a sleek handheld device floating above a hand, soft glow"
• "abstract data visualization with flowing particles"
• "modern office desk with minimal tech accessories"

Avoid:

• Overly detailed color specifications (style is auto-applied)
• Conflicting aesthetic directions (e.g., "vintage rustic style")

Output

• Format: PNG (or JPG/WebP based on API response)
• Resolution: Determined by Gemini model
• Watermark: SynthID embedded (invisible, for authenticity)

Troubleshooting

Error	Solution
No API keys configured	Run keys add <name> <key>
Key 'xxx' not found	Run keys list to see available keys
HTTP 403	Key invalid or lacks permissions
HTTP 429	Rate limited - round-robin helps distribute load
No image generated	Rephrase prompt, avoid restricted content

Security

• Keys stored in ~/.config/nano-banana-image/config.json
• File permissions set to 600 (owner read/write only)
• Keys never logged or displayed in full (masked as AIza...xxxx)
• Fallback to GEMINI_API_KEY environment variable supported

Command Reference

Command	Description
keys list	List all keys with rotation status
keys add <name> <key>	Add a new API key
keys remove <name>	Remove an API key
keys reset	Reset rotation to first key
--check	Check configuration status
--key <name>	Use specific key for one generation