Thank you for telling me that I am ignorant.
What I try to get is some kind of systematic information from you.
And that starts with the file. Usually, one checks the integrity, then the picture file.
if that is OK, then it goes on to the accessibility in your particular environment.
This could have to do with access rights (yes, I know you claim that nothing has changed but still ... why not make sure that these are really still the same).
If the ordinary access has been verified then it could be problems with other programs like virus checkers, indexing programs, e.g. like here:
I would even check if the computer time is the same on all you devices.
But for narrowing down the cause more information has to be supplied by you.