Whenever I try to backup - and I’ve tried to do so onto a flash drive and my hard drive - I keep getting this message: Zipped backup failed with error: zip I/O error: Invalid argument
zip error: Input file read failure (was zipping dissertation.scriv/Files/Docs/1747.jpg).
This message seems pretty explicit. Two things spring to mind.
Make sure you are trying with the latest version of Scriv (redownload the image, as Keith did fix some backup related issues recently)
(And this seems more likely) It would appear that the JPG in question is causing the issue for some reason. Try removing it from the project, making a copy of the original JPG file and re-importing it into the project.
It looks to me as if that specific file is causing the problem, so making a copy and re-importing it should hopefully fix whatever is causing the problem.