Seedance 2.5 image to video: first frame and last frame

To animate a still with Seedance 2.5, send it in frame_images with frame_type: "first_frame"; add a second entry with last_frame to pin the ending. Sume's seedance-2.5 catalog lists first_frame and last_frame, and accepts at most two frame images.

The BytePlus tutorial documents first and last frame as one of its Seedance 2.5 modes.

How do I request it?

Each entry is an image_url object plus a frame_type.

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.5",
    "prompt": "The door slowly opens and warm light spills out",
    "duration": 6,
    "resolution": "720p",
    "aspect_ratio": "16:9",
    "frame_images": [
      {"type": "image_url", "image_url": {"url": "https://example.com/closed.png"}, "frame_type": "first_frame"},
      {"type": "image_url", "image_url": {"url": "https://example.com/open.png"}, "frame_type": "last_frame"}
    ]
  }'

What rules apply on Sume?

These come from the video docs and API validation.

When should I use references instead?

Use frame_images when the still must be an exact frame. Use references when the image only guides look or identity; see image to video vs reference to video.