When you restore a previous version, not only are the screenshots deleted from the version that got reverted, but all screenshots are deleted. While they may appear to still be there the file manager shows them at 0mb and when your cache expires it shows a broken image for every single screenshot uploaded, regardless what version it was added in.

Please could you clarify what you mean here by restore a previous version? Step by step what you are doing would be helpful if possible?

20 minutes ago, Marc Stridgen said:

Please could you clarify what you mean here by restore a previous version? Step by step what you are doing would be helpful if possible?

1. Upload a new version of a file. It doesn't matter if you add more screenshots or not.
2. Go into changelog and select the previous version.
3. Click restore.
4. Now clear your cache and all of the images will be broken. You can verify this by clicking update and scrolling to the screenshot section to see they're all 0mb.