What is the Photos App Tile folder in Windows under "App Data" for?

The following question:

I recently discovered that there's a folder in a fairly well-hidden Windows directory where seemingly random copies of images or screenshots are stored. For me, this folder is located at:

C:Users\Dell\AppData\Local\Packages\Microsoft.Windows.Photos_xxxxxxxxx\LocalState\PhotosAppTile

Overall, not all of the photos were picked out, but only a small number (randomly?), although I actually deleted all of the affected images years ago….

Can anyone tell me how these files got there and what criteria were used? Is it by chance? Is it due to specific content? Is it due to other reasons?

And are there any other similar hidden system folders that might be worth taking a look at?

When I delete something from my system, I normally expect that it is really deleted and that there aren't X hidden copies of it….