Photo recovery with Time Machine

As Richard wrote - here is a link to the page in the user guide explaining how to restore a Photos Library from the Time Machine backup: Restore a library from Time Machine in Photos on Mac

To restore older photos it helps to make occasionally a copy of your Photos Library, in addition to the Time Machine backup. It will be quicker to just open your archived copy, if you just need to find a single image or video.

You can't run Time Machine backups from within Photos. Photos keeps its pictures in a Photos Library, usually titled "Photos Library.photoslibrary" located in your Pictures folder. That's the thing you need to restore, and then you can use the Photos app to access the pictures in it.

I would quit Photos and then open the Pictures folder in Finder. Then run Time Machine-- you should still see the pictures folder with your Photos Library in it. But now you can go back in time and find the Photos Library with the date you want to restore. You can choose to use the restored file to replace the current one, or you can make a copy with a slightly different name.

When that's done (it could take a few minutes depending on the size of the library), open Photos by option-clicking the Photos icon-- it will give a choice of your old or new library.

Good luck, and check with us if you have trouble.