Generate Icon Skill

Generate professional icons for any platform using Gemini AI with automatic background removal, cropping, and multi-size export.

Quick Start

# Favicon for website
bun run icon "modern tech startup logo letter S" --preset favicon --output ./icons/favicon

# iOS App Store icons
bun run icon "meditation app lotus flower" --preset apple-app-icon --output ./icons/ios

# Android Play Store + adaptive icons
bun run icon "fitness tracker flame icon" --preset android-app-icon --output ./icons/android

# PWA manifest icons
bun run icon "productivity app checkmark" --preset pwa --output ./icons/pwa

# macOS desktop app
bun run icon "code editor brackets symbol" --preset macos-icns --output ./icons/macos

# Windows desktop app
bun run icon "music player note icon" --preset windows-ico --output ./icons/windows

# General UI icons
bun run icon "settings gear" --preset ui-icons --output ./icons/ui

Presets

Preset	Description	Sizes	Bundle
apple-app-icon	iOS/iPadOS App Store	18 sizes (1024-20px)	No
android-app-icon	Google Play + adaptive layers	11 sizes + foreground	No
favicon	Browser tab icons	8 sizes + ICO	Yes (.ico)
pwa	Progressive Web App	11 sizes + maskable	No
macos-icns	macOS desktop	10 sizes	Yes (.icns)
windows-ico	Windows desktop	7 sizes	Yes (.ico)
ui-icons	In-app icons	9 sizes (512-16px)	No

Pipeline

1. Generate - Creates master icon at high resolution via Gemini
2. Remove Background - Uses Replicate rembg for clean edges
3. Crop & Center - Trims whitespace, centers on square canvas with 5% padding
4. Resize - Exports all preset sizes with lanczos3 interpolation
5. Bundle - Creates ICO/ICNS bundles where needed

Options

bun run icon "prompt" --preset <name> --output <dir> [options]

Required:
  --preset <name>       Platform preset (see table above)
  --output <dir>        Output directory

Optional:
  --input <image>       Reference image for style guidance
  --master-image <path> Use existing master instead of generating
  --skip-generate       Skip AI generation (requires --master-image)
  --skip-remove-bg      Skip background removal
  --bg-color <hex>      Background color for non-transparent presets

Examples

Using a reference image

bun run icon "clean app icon version" --preset pwa --input ./existing-logo.png --output ./icons

Using an existing master

bun run icon "" --preset ui-icons --master-image ./my-icon.png --skip-generate --output ./icons

iOS with custom background color

bun run icon "weather app sun" --preset apple-app-icon --bg-color "#0066CC" --output ./icons/ios

Icon Design Tips

DO:

• Simple, bold, recognizable silhouette
• Single focal point
• High contrast
• Clean edges
• Works at 16x16px

DON'T:

• Fine details that disappear at small sizes
• Text (unreadable at icon sizes)
• Complex gradients (banding issues)
• Multiple competing elements
• Photos or realistic images

Environment Variables

Variable	Required	Description
GEMINI_API_KEY	Yes	Google AI Studio API key
REPLICATE_API_TOKEN	Yes	Replicate API token for background removal

Output Structure

output/
├── master-raw.png        # Original generated image
├── master-nobg.png       # Background removed
├── master-cropped.png    # Cropped and centered
├── master-final.png      # With background (iOS only)
├── favicon.ico           # ICO bundle (favicon preset)
├── AppIcon.icns          # ICNS bundle (macos preset)
├── icon-512.png          # Size variants...
├── icon-256.png
└── ...

Context Discipline

Do not read generated icon images back into context. The script outputs file paths for all generated sizes. Ask the user to visually inspect the results. Icon sets produce many files across multiple sizes - reading them back would quickly exhaust the context window.

Troubleshooting

Issue	Solution
"GEMINI_API_KEY not set"	Export your API key: export GEMINI_API_KEY=your-key
"REPLICATE_API_TOKEN not set"	Export your token: export REPLICATE_API_TOKEN=your-token
ICO not generated	Install ImageMagick: brew install imagemagick
ICNS not generated	Only works on macOS (requires iconutil)
Background not removed cleanly	Try a simpler prompt with solid background
Icon too complex	Simplify prompt, avoid "detailed" or "realistic"