So with version 2.0, if you have photo backups enabled, you can’t delete a photo on Synology Photos Mobile without also deleting it on your phone. That’s asinine. We should be able to choose whether we want one-way or two-way syncing.
Yeah they’ve really taken away choice, and a lot of people are rightly up in arms over it.
Basically what you have to do is delete a pic (or move it out of the MobileBackup folder) on your NAS, and when the mobile app tells you you’re out of sync, have it ignore the changes. So there is a way to do what you want to do, but it’s absolutely not intuitive.