Seedance 2.5 image to video: your photo decides the aspect ratio

What this tool does

• In VdoBloom's Image to Video tab a Seedance 2.5 photo upload becomes the job's first frame, and first-frame and first-and-last-frame jobs on 2.5 are forced to "adaptive" — the upstream API rejects every other value, so the request is coerced rather than failing after the charge.
• Under adaptive, the output video's shape is inherited from the uploaded image. Crop the photo to the ratio you want before you upload it: 1080x1920 for 9:16, 1920x1080 for 16:9, 1080x1080 for 1:1.
• The adaptive coercion is specific to Seedance 2.5. Seedance 2, Seedance 2 Fast and Seedance 2 Mini pass your chosen aspect ratio through unchanged.
• Seedance 2.5 is selectable in the Image to Video picker, in the same Seedance group as Seedance 2, Seedance 2 Fast, Seedance 2 Mini, Seedance 1.5 Pro and the ByteDance V1 image-to-video variants.
• The Images panel for Seedance models has two modes and opens on Frames (I2V). Frames takes a first frame plus an optional last frame — two images at most — and is what triggers the adaptive coercion on 2.5. Multimodal takes up to 9 reference images and does not, so your chosen ratio is used. The two modes cannot be combined in one request.
• The aspect ratio control in Text to Video and Image to Video offers six values — 16:9, 4:3, 1:1, 3:4, 9:16 and 21:9. Adaptive is not one of them; it is applied server-side on first-frame Seedance 2.5 jobs. The Seedance Effects tab offers all seven, adaptive included.
• For Seedance 2.5 on the Seedance Effects tab, when an effect's stored prompt contains no @Image tag, VdoBloom prepends deterministic reference mentions in the form "Reference @Image1 for the person's face and appearance; reference @Image2 for the scene and visual style."
• On that tab the @ImageN numbering is deterministic: your uploads are numbered first, then the effect's admin reference images. Your clearest face photo should therefore be the first file you upload.
• First-frame and last-frame inputs are mutually exclusive with the reference image, reference video and reference audio inputs — one job cannot mix the two modes. Reference images alone are capped at 9 per job.
• Aspect ratio does not change the price. Seedance 2.5 is billed on resolution and duration only: 9.2 credits per second at 480p and 20.0 at 720p, so a 10-second image-driven clip is 92 or 200 credits regardless of shape.

How it works

1. 1.Crop the photo to your target ratio before anything else

   Do this in whatever editor you already use. For a vertical Reel or Short, export 1080x1920. For YouTube or a landing page, 1920x1080. For a feed square, 1080x1080. Under adaptive this crop is what sets the output shape — you are not going to fix it afterwards with a dropdown.

2. 2.Open Image to Video and pick Seedance 2.5

   Go to /dashboard/video-creation/image-to-video/ and select Seedance 2.5 from the Seedance group in the model list. Doing so expands the duration grid to every second from 4 to 30 and narrows the resolution list to 480p and 720p. If you had 1080p or 4K selected on another Seedance variant, it resets to 480p.

3. 3.Choose Frames or Multimodal deliberately

   The Images panel opens on Frames (I2V): your photo becomes the first frame and you can add an optional last frame, two images at most. That is the mode that forces adaptive on 2.5, and the mode you want when the photo should be the literal opening shot. Switch to Multimodal if you would rather keep control of the aspect ratio — it sends up to nine photos as reference images instead. The two cannot be combined in one request, and switching modes clears the other one's uploads.

4. 4.Write the prompt for the motion, not the look

   This tab has a prompt box and Seedance 2.5 accepts up to 30,000 characters. The photo already sets the subject and the palette, so spend the prompt on what moves: the camera path, the performance beat, how the action resolves. Over a long take, say what happens at roughly which second — 30 seconds is a lot of time to fill with one instruction.

5. 5.Set duration and resolution, then check the cost

   An image-driven job runs the full 30 seconds if you want it: 276 credits at 480p, 600 at 720p. Draft at 480p to confirm the photo animates the way you expected, then re-render the approved take at 720p. Credits are deducted at submission and refunded automatically if the job fails.

6. 6.Check the shape of what comes back

   In Frames mode the returned clip matches your photo, not the ratio control. That is the coercion working as designed rather than a bug — which is why the crop in step one is the real setting. If the shape is wrong, re-crop and re-run; changing the ratio button will not do it.

Frequently asked questions

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