Nano Image Generator

Generate images using Nano Banana Pro (Gemini 3 Pro Preview) for any visual asset needs.

Requirements

Set the GEMINI_API_KEY environment variable. Get a key at: https://aistudio.google.com/apikey

Quick Start

python scripts/generate_image.py "A friendly robot mascot waving" --output ./assets/mascot.png

Script Usage

python scripts/generate_image.py <prompt> --output <path> [options]

Required:

• prompt – Image description
• --output, -o – Output file path

Options:

• --aspect, -a – Aspect ratio (default: 1:1)
  • Square: 1:1
  • Portrait: 2:3, 3:4, 4:5, 9:16
  • Landscape: 3:2, 4:3, 5:4, 16:9, 21:9
• --size, -s – Resolution: 1K, 2K (default), 4K

Workflow

1. Determine output location – Place images where contextually appropriate:

   • App icons → ./assets/icons/ or ./public/icons/
   • Marketing → ./marketing/ or ./assets/images/
   • UI elements → ./src/assets/ or ./public/images/
   • General → ./generated/

2. Craft effective prompts – Be specific and descriptive:

   • Include style: “flat design”, “3D rendered”, “watercolor”, “minimalist”
   • Include context: “for a mobile app”, “website hero image”, “social media post”
   • Include details: colors, mood, composition

3. Choose appropriate settings:

   • Icons/logos → --aspect 1:1
   • Banners/headers → --aspect 16:9
   • Mobile screens → --aspect 9:16
   • Photos → --aspect 3:2 or 4:3

Examples

App icon:

python scripts/generate_image.py "Minimalist flat design app icon of a lightning bolt, purple gradient background, modern iOS style" \
  --output ./assets/app-icon.png --aspect 1:1

Marketing banner:

python scripts/generate_image.py "Professional website hero banner for a productivity app, abstract geometric shapes, blue and white color scheme, modern and clean" \
  --output ./public/images/hero-banner.png --aspect 16:9

High-quality illustration:

python scripts/generate_image.py "Detailed isometric illustration of a cozy home office setup with plants, warm lighting, digital art style" \
  --output ./assets/illustrations/office.png --size 4K

Prompt Tips

• Be specific – “A red apple on a wooden table” vs “an apple”
• Include style – “in the style of pixel art” or “photorealistic”
• Mention purpose – “for a children’s book” affects the output style
• Describe composition – “centered”, “rule of thirds”, “close-up”
• Specify colors – Explicit color palettes yield better results
• Avoid – Don’t ask for text in images (use overlays instead)