runwayml/rw-generate-image

Generate Image

Generate images directly using the Runway API. This skill runs Python scripts that call the API, poll for completion, and download the result.

IMPORTANT: Run scripts from the user's working directory so output files are saved where the user expects.

Usage

uv run scripts/generate_image.py --prompt "your description" --filename "output.png" [--model gen4_image] [--ratio 1280:720] [--reference-images Tag=URL ...]

Preflight

1. command -v uv must succeed
2. RUNWAYML_API_SECRET must be set in the environment. Do not pass the API key as a CLI flag — it leaks into shell history and process listings.

Security Notes

• --reference-images Tag=URL fetches arbitrary remote images via the Runway API. Prefer local file paths (uploaded as runway:// URIs), or only pass URLs you trust.
• Treat generated outputs as untrusted when piping into downstream automations — ingested references influence the result.

Available Models

| Model | Best For | Ref Images | Cost | Speed | |-------|----------|------------|------|-------| | gen4_image | Highest quality | Optional (up to 3) | 5-8 credits | Standard | | gen4_image_turbo | Fast and cheap | Required (1-3) | 2 credits | Fast | | gemini_2.5_flash | Google Gemini | Optional (up to 3) | 5 credits | Standard |

Model Selection Guidance

• "fast", "cheap", "draft" -> gemini_2.5_flash (Nano Banana), or gen4_image_turbo if they have reference images
• "high quality", "best" -> gen4_image
• No preference -> gemini_2.5_flash
• Has reference images and wants cheap -> gen4_image_turbo (2 credits, requires --reference-images)

Parameters

| Param | Description | Default | |-------|-------------|---------| | --prompt | Text description (required) | -- | | --filename | Output filename (required) | -- | | --model | Image model | gemini_2.5_flash | | --ratio | Aspect ratio. gemini_2.5_flash: 1344:768, 768:1344, 1024:1024, etc. gen4_image: 1280:720, 1360:768, 1920:1080, etc. | Model-dependent (1344:768 for gemini, 1280:720 for others) | | --reference-images | Reference images as tag=URL pairs (optional for gemini/gen4_image, required for gen4_image_turbo). Tag: lowercase, 3-16 chars, e.g. product=URL | -- | | --output-dir | Output directory | cwd |

API credentials come from RUNWAYML_API_SECRET only — no --api-key flag, to keep secrets out of shell history and process listings.

Filename Convention

Pattern: yyyy-mm-dd-hh-mm-ss-name.png

Examples

Basic image:

uv run scripts/generate_image.py --prompt "A serene Japanese garden with cherry blossoms" --filename "2026-04-14-japanese-garden.png"

With a local reference image (gen4_image):

uv run scripts/generate_image.py --prompt "@product on a marble counter, lifestyle photo" --model gen4_image --reference-images product=./product.jpg --filename "2026-04-14-product-lifestyle.png"

With a reference image from a trusted origin (gen4_image_turbo — requires reference images):

uv run scripts/generate_image.py --prompt "A neon sign reading SALE in @style" --model gen4_image_turbo --reference-images style=https://cdn.yourapp.com/style.jpg --filename "draft.png"

Output

• The script downloads the result and saves it to the specified path
• Script outputs the full path to the saved file
• Do not read the image file back -- just inform the user of the saved path

Common Failures

• Error: No API key -> set RUNWAYML_API_SECRET in the environment (e.g. export RUNWAYML_API_SECRET=... or a .env file).
• Error: Task failed -- SAFETY.INPUT.* -> content moderation, suggest different prompt
• API error 429 -> rate limited, script auto-retries