If you are doing a file move, then yes indeed its likely related to that, and not any other function.
The reality is, there isnt any way for images to go missing on their own. The only way this can happen is if the source itself is deleted. If you can restore a backup somewhere, we can certainly take a look at that and confirm that this is the case, but in all honesty you are probably chasing an issue around that is simply going to be a user issue, not one on the platform.