A comprehensive, AI-friendly toolkit for professional image generation using Google's Gemini 3 Pro Image (Nano Banana Pro) API.

Made by Ashraf Ali

• 🎨 Multi-Mode Generation: Text-to-image, image editing, and multi-image composition
• 📐 Aspect Ratio Control: Full support for 1:1, 16:9, 9:16, 4:3, 3:2, 21:9, and more
• 🧠 Smart Defaults: Auto-detects optimal settings based on your prompt
• 📝 Prompt Templates: Pre-built templates for logos, products, portraits, and more
• 💬 Interactive Chat Mode: Multi-turn refinement with conversation history
• 🔍 Validation & Warnings: Catches common pitfalls before generation
• 🎯 System Prompts: Enforce consistent styles across all generations
• 🔎 Google Search Grounding: Real-time data for infographics and current events

# Clone the repository
git clone https://github.com/nerveband/nb-pro-image-gen-skill.git
cd nb-pro-image-gen-skill

# Set your API key
export GEMINI_API_KEY="your-api-key-here"

# Basic generation
uv run scripts/generate_image.py \
  -p "A serene mountain landscape at sunset" \
  -f landscape.png

# With aspect ratio
uv run scripts/generate_image.py \
  -p "Epic cinematic cityscape" \
  -f city.png \
  --aspect 21:9

# Using a template
uv run scripts/generate_image.py \
  --template photorealistic \
  --template-var subject="A majestic lion" \
  --template-var action="roaring" \
  --template-var setting="African savanna" \
  -f lion.png

• Complete Usage Guide
• Prompt Templates
• Best Practices
• API Reference
• Examples

uv run scripts/generate_image.py \
  --prompt "Your description here" \
  --filename output.png

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

# Social media story (vertical)
uv run scripts/generate_image.py \
  -p "Quote graphic with bold typography" \
  -f story.png \
  --aspect 9:16

# Cinematic widescreen
uv run scripts/generate_image.py \
  -p "Movie poster design" \
  -f poster.png \
  --aspect 21:9

Enable automatic setting detection based on prompt content:

uv run scripts/generate_image.py \
  -p "Professional headshot for LinkedIn" \
  -f portrait.png \
  --smart
# Auto-selects: aspect=3:4, thinking=high

Auto-detection works for:

• Logos → 1:1 aspect, text optimization
• Portraits → 3:4 aspect, high quality
• Landscapes → 16:9 aspect
• Products → 4:3 aspect, commercial style
• Social media → 9:16 or 1:1 aspect

Edit existing images with text instructions:

uv run scripts/generate_image.py \
  -p "Add dramatic sunset colors and lens flare" \
  -f edited.png \
  -i original.png

Combine up to 14 reference images:

uv run scripts/generate_image.py \
  -p "Family portrait with everyone smiling" \
  -f family.png \
  -i person1.png -i person2.png -i person3.png

Perfect for iterative refinement:

uv run scripts/chat_image.py

Example session:

> Create a logo for my coffee shop "Daily Grind"
[Image generated]
> Make it more minimalist and use earth tones
[Refined image]
> Add a coffee bean icon above the text
[Refined image]
> /save daily_grind_logo.png
Saved: /path/to/daily_grind_logo.png

Chat Commands:

• /save <filename> - Save the last generated image
• /aspect <ratio> - Change aspect ratio (clears history)
• /resolution <size> - Set resolution (1K, 2K, 4K)
• /search - Toggle Google Search grounding
• /clear - Clear conversation history
• /config - Show current settings
• /help - Show help
• exit or quit - Exit chat

Use structured templates for consistent, professional results:

photorealistic: Professional photography with camera specs

uv run scripts/generate_image.py \
  --template photorealistic \
  --template-var subject="A majestic lion" \
  --template-var action="roaring" \
  --template-var setting="African savanna at golden hour" \
  --template-var camera_angle="low angle shot" \
  --template-var lighting="warm golden hour backlighting" \
  --template-var lens="200mm telephoto" \
  --template-var mood="powerful and majestic" \
  -f lion.png

product: E-commerce product photography

uv run scripts/generate_image.py \
  --template product \
  --template-var product="artisan coffee beans in kraft bag" \
  --template-var surface="rustic wooden table" \
  --template-var lighting="soft natural window light" \
  --template-var angle="45-degree angle" \
  --template-var style="minimalist lifestyle" \
  -f coffee.png

logo: Clean logo designs

uv run scripts/generate_image.py \
  --template logo \
  --template-var style="minimalist" \
  --template-var elements="coffee bean and steam" \
  --template-var colors="black and white" \
  --template-var typography="sans-serif" \
  --template-var background="white" \
  -f logo.png

portrait: Professional portraits

uv run scripts/generate_image.py \
  --template portrait \
  --template-var subject="confident businesswoman" \
  --template-var pose="three-quarter view" \
  --template-var lens="85mm" \
  --template-var lighting="soft studio lighting" \
  --template-var background="neutral gray" \
  --template-var mood="professional and approachable" \
  -f portrait.png

social: Social media graphics

uv run scripts/generate_image.py \
  --template social \
  --template-var aspect="9:16" \
  --template-var headline="Summer Sale" \
  --template-var visual="beach sunset with palm trees" \
  --template-var details="50% OFF - This Weekend Only" \
  -f instagram_story.png

Every prompt should include:

1. Subject - Who or what
2. Composition - How it's framed
3. Action - What's happening
4. Location - Where
5. Style - Aesthetic

Example:

Create a cinematic portrait of a jazz musician [subject] 
playing saxophone [action] on a rainy Paris street [location], 
shot from a low angle [composition]. The style is realistic 
with moody blue and orange lighting [style].

• Use natural, full-sentence descriptions
• Be specific about camera angles, lighting, lenses
• Use "MUST" and "NEVER" for strict constraints
• Limit text to 1-3 elements per image
• Include negative constraints ("no text", "no watermarks")
• Use reference images for consistency
• Specify aspect ratios for your use case

• Use keyword soup ("beautiful amazing stunning")
• Request conflicting styles (photorealistic + cartoon)
• Expect perfect small text rendering
• Use 500+ word prompts
• Be vague about technical specs

Vague descriptions: ❌ "A picture of a cat" ✅ "A tabby cat lounging in a sunlit window, warm afternoon light, cozy home interior"

Conflicting styles: ❌ "Photorealistic cartoon character" ✅ "Cartoon character in Pixar 3D animation style"

Text overload: ❌ "Poster with title, subtitle, 5 bullet points, footer text" ✅ "Minimalist poster with bold headline only"

uv run scripts/generate_image.py \
  -p "Clean black-and-white logo with text 'Daily Grind', sans-serif font, coffee bean icon, minimalist style" \
  -f logo.png \
  --aspect 1:1 \
  --smart

uv run scripts/generate_image.py \
  -p "Studio-lit wireless earbuds on polished concrete, 3-point softbox lighting, 45-degree angle, professional e-commerce style" \
  -f product.png \
  --aspect 4:3 \
  --resolution 4K

# Step 1: Create base character
uv run scripts/generate_image.py \
  -p "Character reference: young wizard with blue robes, silver staff, friendly smile" \
  -f wizard_ref.png \
  --aspect 1:1

# Step 2: Use as reference for scenes
uv run scripts/generate_image.py \
  -p "The wizard casting a spell in an ancient library" \
  -f wizard_library.png \
  -i wizard_ref.png \
  --aspect 16:9

uv run scripts/generate_image.py \
  -p "Instagram story: bold text 'New Collection' at top, fashion model in center, website at bottom, high contrast" \
  -f story.png \
  --aspect 9:16 \
  --smart

Required Arguments:

• --prompt, -p: Image description/prompt
• --filename, -f: Output filename

Optional Arguments:

• --input-image, -i: Input image(s) for editing (can specify multiple)
• --resolution, -r: Output resolution (1K, 2K, 4K) - default: 1K
• --aspect, -a: Aspect ratio (1:1, 16:9, 9:16, etc.)
• --smart: Auto-detect optimal settings
• --system, -s: System prompt for consistent constraints
• --search: Enable Google Search grounding
• --template: Use predefined template
• --template-var: Template variables (KEY=VALUE)
• --validate: Enable prompt validation (default: True)
• --no-validate: Disable validation
• --api-key, -k: Gemini API key

Interactive mode with no required arguments. Set GEMINI_API_KEY environment variable.

Commands:

• Type prompts naturally for generation
• /save <filename> - Save image
• /aspect <ratio> - Change aspect ratio
• /resolution <size> - Change resolution
• /search - Toggle search grounding
• /clear - Clear history
• /config - Show settings
• /help - Show help
• exit or quit - Exit

1. Visit Google AI Studio
2. Create an account or sign in
3. Go to API Keys section
4. Create a new API key
5. Set the environment variable:

   export GEMINI_API_KEY="your-api-key-here"

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

This project is licensed under the MIT License - see the LICENSE file for details.

• Built on Google's Gemini 3 Pro Image API
• Inspired by the Nano Banana Pro model
• Thanks to the Google AI team for the amazing image generation capabilities

• Create an issue for bug reports
• Start a discussion for questions

Happy generating! 🎨✨