Zip is authorised. Please try again because those images are part of your mlt project and will assist in identifying the issue (unless someone else like @Hudson555x can solve the problem before you manage to complete that task)!
Edit: I think he may have done just that so if their suggestion fixes it don’t worry (but you should still be able to do it regardless).
It can handle gaps of up to 100 in the sequence file name. Part of the problem is poor communication. This is not a typical image sequence where a high frame rate animation or video is saved as a separate image per frame. It is more like a sequence of shots where each shot should be shown for some time. Hence, the Properties > Repeat mentioned above. The other issue is related to speed of preview giving the wrong impression. Preview is not able to able to decode and play these 6000x4000 JPEG photos in realtime one frame per 16.6 ms. So, it plays as fast it can but slowly giving the impression it will show each image a second or so, which is not what it will be like after export. Sorry but I cannot make the preview for this faster and realtime, and proxy does not support image sequence. The user needs to do more mental mapping of images to frames-per-second. Either use the Repeat option, do not make it an image sequence, or use the slideshow generator.
Indeed - mine! Apologies for giving the incorrect information… I hold my hands up to that.
I never knew that. @shotcut, is this a change in a recent SC version? I could have sworn that you had to have all photos with an increment of 1…
Anyway, I just tried this out and made a short screen capture of the process and it works, using 15 frames per image. Hope this is helpful to the OP.
Another way of achieving reverse order with image sequence would be to copy/paste the photos and rename them in reverse order, the last one as 01.png, the next-but-last as 02.png, etc, then run the image sequence process.