Asset Generator

AI Asset Generator

Generate production-ready image assets for web and mobile apps using Google Gemini 3 Pro Image (Nano Banana Pro).

Setup

Install dependencies (one-time):

pip3 install -r ~/.cursor/skills/asset-generator/scripts/requirements.txt

Set your Gemini API key (one-time):

python3 ~/.cursor/skills/asset-generator/scripts/setup_key.py YOUR_GEMINI_API_KEY

First use of --transparent downloads the rembg model (~170MB). Subsequent runs are fast.

Quick Reference

Generate an asset

python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py "a friendly robot" \
  --style icon --transparent --output robot_icon.png

Generate with reference images

Use --ref to pass images that Gemini incorporates into the output. Place {image1}, {image2}, etc. in your prompt to control where each reference appears:

# Edit/restyle a single reference (image placed before text for optimal results)
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "redesign this icon in a modern flat style with blue and purple tones" \
  --ref old_icon.png --style icon --transparent -o modern_icon.png

# Incorporate a screenshot into a generated scene
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "a rabbit using a computer that shows {image1} on screen" \
  --ref screenshot.png --style illustration -o rabbit_at_computer.png

# Multiple references (up to 14)
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "combine the style of {image1} with the logo from {image2} into a new app icon" \
  --ref style_ref.png --ref logo.png --style icon --transparent -o new_icon.png

# Brand consistency: use 3-5 reference images
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "create a new marketing banner maintaining the exact brand style, colors, and typography from these references" \
  --ref brand1.png --ref brand2.png --ref brand3.png --style marketing -ar 16:9 -o banner.png

Remove background from any image

python3 ~/.cursor/skills/asset-generator/scripts/remove_bg.py input.png --output transparent.png

Export to platform-specific sizes

python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py icon.png --preset ios-icon --output icons/

List available style presets

python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py --list-styles

generate_asset.py Options

Style Presets

Style presets are defined in scripts/styles.json and can be customized or extended.

Model

This skill uses Gemini 3 Pro Image (gemini-3-pro-image-preview), Google's most advanced image generation model. Key capabilities:

Use --thinking high (default) for best quality on complex compositions. Use --thinking low for faster generation on simple prompts.

Reference Images - Best Practices

Gemini 3 Pro Image natively understands reference images through its Thinking mode -- no pre-processing or description step needed.

Placement strategy

• Single reference, no placeholder: Image is placed before the text prompt (optimal for edits/restyling)
• With {imageN} placeholders: Images are interleaved at the exact position in the prompt
• Multiple references, no placeholders: Each image gets a labeled role description

Tips for best results

• Be explicit about each image's role: "Use the colors from {image1}", "match the art style of {image1}", "display {image1} on the monitor screen"
• For brand consistency: Upload 3-5 reference images of existing brand assets
• For character consistency: Include character reference and specify "maintain exact facial features and characteristics"
• For style transfer: Place the style reference first, then describe the new subject
• Keep prompts natural: Gemini 3 Pro understands conversational language better than keyword-stuffed prompts
• Don't over-prompt: Avoid "4k, trending on artstation, masterpiece" -- the model handles quality natively

Background Removal

Gemini cannot natively generate transparent images. This skill uses a smart two-step approach:

1. Smart color picking: Analyzes the prompt text and reference images to choose a solid background color (from magenta, green, blue, red, cyan, yellow) that doesn't conflict with the subject's colors. For example, a "green stethoscope vet dog" prompt will avoid green and pick magenta instead.
2. Chroma-key removal: After generation, removes the chosen background color using fast, precise chroma keying with anti-aliased edges. Falls back to rembg ML if no chroma color is available.

The --transparent flag handles both steps automatically. The chosen background color is printed during generation.

Standalone background removal

# ML-based (best quality, for arbitrary photos)
python3 ~/.cursor/skills/asset-generator/scripts/remove_bg.py photo.jpg --output clean.png

# Chroma key (fast, for solid-color backgrounds)
python3 ~/.cursor/skills/asset-generator/scripts/remove_bg.py greenscreen.png --method chroma --color 00FF00
python3 ~/.cursor/skills/asset-generator/scripts/remove_bg.py magenta_bg.png --method chroma --color FF00FF

# Batch process a directory
python3 ~/.cursor/skills/asset-generator/scripts/remove_bg.py images/ --batch --output transparent/

Platform Export (resize_assets.py)

Export a source image to all sizes needed for a platform:

python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py icon.png --preset ios-icon --output ios/
python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py icon.png --preset android-icon --output android/
python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py icon.png --preset favicon --output public/
python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py icon.png --preset pwa-icon --output pwa/
python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py banner.png --preset social-media --output social/

Export Presets

Custom sizes

python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py icon.png --sizes "64,128,256,512" --output sizes/
python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py banner.png --sizes "1200x630,1080x1080" --output custom/

Common Workflows

Generate app icon set for iOS and Android

# 1. Generate the master icon
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py "a rocket ship" \
  --style icon --transparent --resolution 2K --output master_icon.png

# 2. Export for iOS
python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py master_icon.png \
  --preset ios-icon --output ios-icons/

# 3. Export for Android
python3 ~/.cursor/skills/asset-generator/scripts/resize_assets.py master_icon.png \
  --preset android-icon --output android-icons/

Generate consistent illustration set

# Generate first asset
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py "a shopping cart" \
  --style illustration --output assets/cart.png

# Use it as style reference for subsequent assets (image placed before text automatically)
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "a credit card in the same visual style as {image1}" \
  --ref assets/cart.png --style illustration --output assets/card.png

python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "a delivery truck in the same visual style as {image1}" \
  --ref assets/cart.png --style illustration --output assets/truck.png

Marketing materials with accurate text

# Gemini 3 Pro Image excels at rendering text accurately
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "a minimalist movie poster titled 'THE SILENT ECHO' in large distressed sans-serif font at the top, with a lone cabin in a snowy forest viewed from above, high contrast black and white" \
  --style marketing --resolution 2K -o poster.png

# Infographic with accurate labels
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "a step-by-step infographic showing how to brew pour-over coffee, clean vector art with pastel colors, label all ingredients correctly" \
  --style infographic --resolution 2K -o coffee_infographic.png

Incorporate screenshots or photos into generated art

python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "a cute owl mascot sitting at a desk, looking at a monitor that displays {image1}" \
  --ref website_screenshot.png --style mascot -o mascot_at_work.png

python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "a hand holding {image1} with a beautiful sunset background" \
  --ref product_photo.png --style photo -ar 16:9 -o hero_product.png

Generate landing page hero image

python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py \
  "abstract technology network with glowing nodes and connections, deep blue to purple gradient" \
  --style hero --resolution 2K --output hero.png

Generate multiple variations and pick the best

python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py "a friendly owl mascot" \
  --style mascot --count 4 --transparent --output owl.png
# Generates: owl_1.png, owl_2.png, owl_3.png, owl_4.png

Fast iteration with low thinking

# Use --thinking low for quick drafts during ideation
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py "a space helmet" \
  --style icon --thinking low --transparent --output draft_helmet.png

# Then use --thinking high (default) for the final version
python3 ~/.cursor/skills/asset-generator/scripts/generate_asset.py "a space helmet" \
  --style icon --transparent --resolution 2K --output final_helmet.png

Configuration

Config stored at ~/.cursor/skills/asset-generator/config.json:

{
  "gemini_api_key": "YOUR_KEY",
  "default_style": "illustration",
  "default_format": "png"
}

Update defaults:

python3 ~/.cursor/skills/asset-generator/scripts/setup_key.py --set-default-style icon
python3 ~/.cursor/skills/asset-generator/scripts/setup_key.py --show

Additional Resources

• For advanced prompt engineering, custom styles, and API details, see REFERENCE.md