Recovering photos from my old external drive if it’s no longer recognized by iMac
I was using an external hard drive for all my Time Machine backups and apparently my photos. I don't even know how the photos were saved there, but my external drive was getting old so I purchased a new one and with both connected, did a new back up. Shortly after my original external drive no longer would work. I tried to access my photos and it said "Photos cannot find library "photos library.photoslibary" This library was last found on a drive named "Backup". Please attach that drive and click "Try Again". I thought when my iMac backed up to my new Time Machine backup it would back up everything but now I cannot access my pictures. I don't know what to do. My grandfather just passed away and I am trying to access pictures of him. Even if I get my old hard drive transferred to my new external drive, how am I supposed to acmes my pictures if it is only being associated with my old "backup"? Please help.
[Re-Titled by Moderator]
Original Title: Photo Cannot Be Located
iMac 21.5″, macOS 10.15