Missing pictures in Photos

Hi:

Major disaster here. My Mac started crashing all the time so I restored it from backup. Restoration went fine except some pictures won't load after completing the restore.

All of the recent pictures are just fine, only some of the more recent ones show up, and with rare exceptions, none of the old ones appear. My Library looks like this:

Any ideas what would cause this, and, more importantly, how to fix it?

Many thanks!!!

Mac Studio 2022 (M1) running OS 13.3.1 and Photos Version 8.0 (541.0.120)