Image Generation
Generate images from text prompts using OpenAI, Google Imagen, Nano Banana Pro (Gemini), or fal.ai.
Usage
OpenAI (gpt-image-1)
uv run ~/.claude/skills/image-gen/scripts/generate_openai.py \
--prompt "a cat wearing a top hat" \
--output /tmp/cat.pngOptions:
--prompt(required): Text description of the image--output,-o: Output file path (default:./generated-{timestamp}.png)--size: Image size (default:1024x1024, options:1024x1024,1024x1792,1792x1024)--quality: Image quality (default:auto, options:low,medium,high,auto)
Google Imagen 4
uv run ~/.claude/skills/image-gen/scripts/generate_imagen.py \
--prompt "a cat wearing a top hat" \
--output /tmp/cat.pngOptions:
--prompt(required): Text description of the image--output,-o: Output file path (default:./generated-{timestamp}.png)--model: Model to use (default:imagen-4.0-generate-001, options:imagen-4.0-fast-generate-001,imagen-4.0-ultra-generate-001)
Nano Banana Pro (Gemini)
uv run ~/.claude/skills/image-gen/scripts/generate_gemini.py \
--prompt "a cat wearing a top hat" \
--output /tmp/cat.pngOptions:
--prompt(required): Text description of the image--output,-o: Output file path (default:./generated-{timestamp}.jpg)--model: Model to use (default:gemini-3-pro-image-preview)--aspect-ratio,-a: Aspect ratio (default:1:1, options:1:1,16:9,9:16,21:9)--image-size,-s: Output size for Pro model (options:1K,2K,4K)
fal.ai (Flux)
uv run ~/.claude/skills/image-gen/scripts/generate_fal.py \
--prompt "a cat wearing a top hat" \
--output /tmp/cat.pngOptions:
--prompt(required): Text description of the image--output,-o: Output file path (default:./generated-{timestamp}.png)--model: Model to use (default:fal-ai/flux/dev)
Provider Comparison
| Provider | Model | Speed | Quality | Cost |
|---|---|---|---|---|
| OpenAI | gpt-image-1 | Medium | Excellent | ~$0.04/img |
| Imagen 4 | Medium | Excellent | ~$0.04/img | |
| Nano Banana Pro | Fast | Excellent | ~$0.13/img (2K) | |
| fal.ai | Flux dev | Fast | Very good | Pay-per-compute |
Environment Variables
| Provider | Variable | Required |
|---|---|---|
| OpenAI | OPENAI_API_KEY | Yes |
GOOGLE_API_KEY | Yes | |
| fal.ai | FAL_KEY | Yes |
Set in ~/.env or export in shell.
Troubleshooting
Getting API Keys
| Provider | Get Key URL |
|---|---|
| OpenAI | https://platform.openai.com/api-keys |
| https://aistudio.google.com/apikey | |
| fal.ai | https://fal.ai/dashboard/keys |
Common Errors
"API key not set"
# Add to ~/.env
echo "GOOGLE_API_KEY=your-key-here" >> ~/.env
# Or export in current shell
export GOOGLE_API_KEY=your-key-here"API key is invalid"
- Regenerate your key at the provider's dashboard
- Ensure no extra whitespace when copying the key
- Check the key hasn't expired
"Rate limit exceeded"
- Wait 1-2 minutes and retry
- Check your usage quota at the provider's dashboard
"Content blocked"
- The prompt triggered safety filters
- Rephrase to avoid restricted content
"Cannot connect"
- Check your internet connection
- Verify the API service isn't experiencing outages
File Format Notes
- OpenAI: Returns PNG
- Google Imagen: Returns PNG
- Google Gemini: Returns JPEG (scripts auto-correct extension if needed)
- fal.ai Flux: Returns JPEG (scripts auto-correct extension if needed)
Testing
uv run ~/.claude/skills/image-gen/tests/test_image_gen.py --help