generate-image

What this skill does

# Generate Image

Generate and edit high-quality images using OpenRouter's image generation models including FLUX.2 Pro and Nano Banana Pro (Gemini 3 Pro).

## Quick Start

Use the `scripts/generate_image.py` script to generate or edit images:

```bash
# Generate a new image
python scripts/generate_image.py "A beautiful sunset over mountains"

# Edit an existing image
python scripts/generate_image.py "Make the sky purple" --input photo.jpg
```

This generates/edits an image and saves it as `generated_image.png` in the current directory.

## API Key Setup

**CRITICAL**: The script requires an OpenRouter API key. Before running, check if the user has configured their API key:

1. Look for a `.env` file in the project directory or parent directories
2. Check for `OPENROUTER_API_KEY=<key>` in the `.env` file
3. If not found, inform the user they need to:
   - Create a `.env` file with `OPENROUTER_API_KEY=your-api-key-here`
   - Or set the environment variable: `export OPENROUTER_API_KEY=your-api-key-here`
   - Get an API key from: https://openrouter.ai/keys

The script will automatically detect the `.env` file and provide clear error messages if the API key is missing.

## Model Selection

**Default model**: `google/gemini-3-pro-image-preview` (high quality, recommended)

**Available models for generation and editing**:
- `google/gemini-3-pro-image-preview` - High quality, supports generation + editing
- `black-forest-labs/flux.2-pro` - Fast, high quality, supports generation + editing

**Generation only**:
- `black-forest-labs/flux.2-dev` - Development version, generation only

Select based on:
- **Quality**: Use gemini-3-pro or flux.2-pro
- **Editing**: Use gemini-3-pro or flux.2-pro (both support image editing)
- **Cost**: Use flux.2-dev for generation only

## Common Usage Patterns

### Basic generation
```bash
python scripts/generate_image.py "Your prompt here"
```

### Specify model
```bash
python scripts/generate_image.py "A cat in space" --model "black-forest-labs/flux.2-pro"
```

### Custom output path
```bash
python scripts/generate_image.py "Abstract art" --output artwork.png
```

### Edit an existing image
```bash
python scripts/generate_image.py "Make the background blue" --input photo.jpg
```

### Edit with a specific model
```bash
python scripts/generate_image.py "Add sunglasses to the person" --input portrait.png --model "black-forest-labs/flux.2-pro"
```

### Edit with custom output
```bash
python scripts/generate_image.py "Remove the text from the image" --input screenshot.png --output cleaned.png
```

### Multiple images
Run the script multiple times with different prompts or output paths:
```bash
python scripts/generate_image.py "Image 1 description" --output image1.png
python scripts/generate_image.py "Image 2 description" --output image2.png
```

## Script Parameters

- `prompt` (required): Text description of the image to generate, or editing instructions
- `--input` or `-i`: Input image path for editing (enables edit mode)
- `--model` or `-m`: OpenRouter model ID (default: google/gemini-3-pro-image-preview)
- `--output` or `-o`: Output file path (default: generated_image.png)
- `--api-key`: OpenRouter API key (overrides .env file)

## Error Handling

The script provides clear error messages for:
- Missing API key (with setup instructions)
- API errors (with status codes)
- Unexpected response formats
- Missing dependencies (requests library)

If the script fails, read the error message and address the issue before retrying.

## Notes

- Images are returned as base64-encoded data URLs and automatically saved as PNG files
- The script supports both `images` and `content` response formats from different OpenRouter models
- Generation time varies by model (typically 5-30 seconds)
- For image editing, the input image is encoded as base64 and sent to the model
- Supported input image formats: PNG, JPEG, GIF, WebP
- Check OpenRouter pricing for cost information: https://openrouter.ai/models

## Image Editing Tips

- Be specific about what changes you want (e.g., "change the sky to sunset colors" vs "edit the sky")
- Reference specific elements in the image when possible
- For best results, use clear and detailed editing instructions
- Both Gemini 3 Pro and FLUX.2 Pro support image editing through OpenRouter