OK, no problem. Assuming you are bringing in the images into Photos when you import them, there is a database of all those images that should be backed up as a database. You can see where it is by opening Photos, going to Preferences and on the "General" tab at the top of the window it will show the path to the database. What you can do is check to see where it is, then enter TM and go back to any date in the past, navigate to that location and see what the size of the photos database is and compare that with what it is on the regular place. If they are the same size, you can be reasonably comfortable that the entire database is backed up.
About the only way to see if all the images are actually inside the database is to move the current database somewhere else, then store from TM the backed up copy and see if the images are there. Then delete the restored one and put back the current one. But that's not really necessary unless you are really paranoid, in which case what you really should do is to make a clone backup as well as a TM backup using something like Carbon Copy Cloner or SuperDuper! to make the clone. And use two different drives, one for TM and a second one for CCC. And if you are REALLY paranoid like me, you then make a third copy onto a network attached drive of the really critical files and maybe even consider putting a copy on a drive that you store in a safety deposit box at your bank. (I haven't gone quite that far, yet.) Pick your level of paranoia and go with it!
