"You don't have permission" warning in Preview

I do a lot of photo editing using Preview. Lately, I have been having some odd issues related to permissions. When I make a copy of one of my own photos, it labels as, for example, "DSCN21497 copy." Then, if I click on the copy, I get a message, "The document 'DSCN21497 copy' could not be saved as 'DSCN21497 copy'. You don't have permission." If I then click "OK," the warning goes away, and I can edit my photo.

I am still able to get my work done, but that pops up with EVERY photo I work on, so it is quite a nuisance.

I am running Sonoma 14.5 on a 2021 MacBook Pro. I have tried running Disk First Aid, and I have reinstalled the system. Nothing changes.

How can I get rid of this warning?