Restrictions on screenshots and videos in snap listings


Do a snap’s screenshots have, and if not should they have:

  • A maximum number? (We just tested uploading 18 screenshots, with no error. I’d suggest a maximum of 4 or 5, not counting banner graphics.)
  • Minimum dimensions? (The upload form seems to accept a 10 px × 10 px “screenshot”, which would be obviously a mistake.)
  • Maximum dimensions? (The upload form seems to accept a 10000 px × 6000 px “screenshot”. Any sufficiently large image is effectively a DoS for end users.)
  • A maximum file size?
  • Any restrictions on aspect ratio? (A “screenshot” that’s 3840 px × 100px might be within allowed dimensions, but it would look like a malfunction to store users.)
  • Any restrictions on animation? (That is, what happens if you try to upload an APNG?)

Separately, should it be possible to upload videos? Other stores allow this. If so, they should also be limited in number (I’d suggest 1), dimensions, duration, and file size.

These questions are important because they influence the UI for uploading and ordering. For example, the easiest UI for organizing screenshots is quite different if the maximum number is 4 than if it’s 30.


In the absence of any other input … here’s a straw-person proposal for screenshots:

  • Maximum number: 4
  • Minimum dimensions: 640 px × 640 px
  • Maximum dimensions: 4096 px × 2160 px (the biggest common 4K variant)
  • Maximum file size: 20 MB
  • Aspect ratio: from 1:3 to 3:1
  • Animation: none

And for videos:

  • Maximum number: 1
  • Minimum dimensions: 640 px × 640 px
  • Maximum dimensions: 4096 px × 2160 px
  • Minimum duration: 10 seconds
  • Maximum duration: 30 seconds
  • Maximum file size: 50 MB
  • Aspect ratio: from 1:3 to 3:1


I think we need to take into account what restrictions Gnome Software has for screenshots @willcooke ?


Paging @robert.ancell, our GNOME Software guru.

Show screenshots on the web store?

GNOME Software has no limitation on the number of screenshots, though it doesn’t handle it particularly well (this is 100 screenshots):

It also doesn’t limit the screenshot sizes.

Appstream supports any number of screenshots in any size, though it doesn’t explicitly support videos. I’ve pinged the authors to see if it would need a new <video> tag or supplying a .avi (exactly what codecs are supported would need to be defined) for a screenshot would be sufficient here. Either way video support could be added to GNOME software but it doesn’t have it today.


I think the proposal on the screenshot image parameters makes sense, we can look at what’d be needed to implement this and come back with any needed changes to the idea.

Storing/handling videos is out of scope for the snap store. We can discuss adding external video URLs as snap metadata but should do so on a new thread.