Photos don't show

1. When I first opened photos, I could right click and see the information about the photo but could not see the photo. Slowly as I clicked on each photo they began showing up; however, I am now back in 2014, and many of the photos, again I can see the info (such as the f-stop, the ISO and the camera type) but no photo. The farther I go back from 2014, the fewer photos are appearing.
2. When I try to, for instance, locate all photos for a certain person, only a few of the photos (amongst the many that the "search" bar says are available will appear. It is far more than when I first opened photos up, but still not the entire lot.
3. I tries to read about photos with the change from El Capitan to Mojave and it said something to the effect that it was scanning photos in to the new photos, but some of these photos have not appeared at exactly the same time, with the same camera and the same size for 48 hours. I think that the most frustrating thing is that I can right click and see what the photo is, and all the info about the photo, just cannot see the photo.
4. As I said, All the photos that previously were not appearing in the beginning from 2021 to 2014 have appeared, but beginning in late 2014, fewer and fewer photos are appearing, only their data.
5. I hope that this makes more sense.

It still seems so odd that the very same camera with the very same size photos are not visible when others are. But, I will keep hoping. Thanks for your reply and I will ask one of my apple guru buddies to take a look when he gets back to town.

Tks again