[IshKebab]

I think you misunderstood - they finish at exactly 75%, which means it should be easy to make them all finish at 100% as they should.

There's an obvious explanation for why they finish at 75% though - to export a photo it presumably has to download it, and then do "something else" (maybe format conversion?). Measuring download progress is easy, but presumably the "something else" was more difficult to measure the progress on. Most libraries don't give progress feedback for most operations.

So the developer just thought "screw it, we'll allow 25% of the time for that processing". Based on the video they were wildly off but accurate progress bars are really low priority for a reason.