Your job failed, your credits came back, and the error told you almost nothing:
Error while downloading image, error: expected the aspect ratio to be between 0.40 and 2.50, but received image with aspect ratio: 2.80 instead
That is a real error from a real job on our platform. Here is what it means, which of your images caused it, and why we can only tell you this for two model families out of the several dozen we run.
What the number is
Aspect ratio here is width ÷ height, not the "16:9" label you picked in the panel. It is measured on the reference image you attached, not on the video you asked for.
Seedance accepts reference images between 0.40 and 2.50. Anything wider or taller than that is rejected upstream — after you submit, not before.
| Your image | Width ÷ height | Seedance |
|---|---|---|
| 9:21 ultra-tall | 0.429 | accepted |
| 9:16 portrait | 0.563 | accepted |
| 3:4 portrait | 0.750 | accepted |
| 1:1 square | 1.000 | accepted |
| 16:9 landscape | 1.778 | accepted |
| 21:9 ultrawide | 2.333 | accepted |
| 2.35:1 anamorphic | 2.350 | accepted |
| 3:1 banner | 3.000 | rejected |
| 1:3 vertical strip | 0.333 | rejected |
Roughly: anything between a 2:5 portrait and a 5:2 landscape is fine. Panorama crops, banner strips and stitched filmstrips are what break it.
Where this number came from
Not from documentation. We could not find this limit published anywhere.
It came out of one failed job on 2026-09-04. A user submitted a Seedance 2.5 reference-to-video job with three reference images, it failed, they retried 80 seconds later, and it failed again. Both times: submit, wait, fail, refund. Both times the error named an aspect ratio but not which image had it.
So we downloaded all three images from that job and measured them:
| Pixel size | Width ÷ height | ||
|---|---|---|---|
| Image 1 | 1584 × 2816 | 0.563 | fine |
| Image 2 | 2160 × 3840 | 0.563 | fine |
| Image 3 | 2048 × 731 | 2.802 | over the limit |
Two perfectly ordinary portrait images and one wide crop. The wide one killed the job — twice — and nothing in the error pointed at it.
The same image is legal on a different model
This is the part worth knowing before you re-crop anything.
| Model | Reference image aspect ratio | Where the limit comes from |
|---|---|---|
| Seedance family | 0.40 – 2.50 | the production error above — measured on 2.5; the rest of the family shares an adapter but has not been tested individually |
| Wan 3.0 | up to 8:1 → 0.125 – 8.0 | Alibaba Bailian official API docs |
| Everything else | we don't know | — |
That 2048 × 731 image at 2.802 is rejected by Seedance and completely legal on Wan 3.0. The two known limits differ by more than a factor of three.
Why we don't just block it for you
The obvious fix is to reject the image in our own interface before you spend anything. We considered that and decided against it, and the table above is the reason: we know two limits out of several dozen models. Blocking on a number we don't have means refusing images that would have worked fine.
So the submission always goes through. If you know something we don't about a model we haven't measured, we are not going to stop you on a guess.
The cost of that choice is the one you are paying right now: when the upstream rejects the image, the error names a ratio and not a filename. Until our own limits table covers more than two models, the check below is faster than waiting for the job to fail.
Our internal table has exactly two entries in it. When we learn a third — from documentation, or from a failure like this one — it gets added.
If you hit this right now
- Take the width and height in pixels of each reference image and divide width by height.
- Any result below 0.40 or above 2.50 is the culprit on Seedance.
- Crop toward the subject rather than scaling — you want the frame narrower, not the content squashed.
- Or run that same image on Wan 3.0, where up to 8:1 is fine.
A rejected job is refunded. What you lose is the wait.