Can deleted photos be retrieved from Deleted Files?

3 days ago I deleted some individual in-named, un-filed single iPhone uploaded pictures. A few minutes ago I tried retrieving some from the deleted files section and after adjusting the filters, nothing came up.  (1)Is there a grace period for retrieving? (2)Are deleted files the only items retrievable and not individual un-filed pictures? I’m a bit confused as to (3)what the difference between files and phone uploads and camera uploads are other than the obvious, deleting un-filed un-named singles individually to files having a name, files holding multiple pictures and ability to delete a whole file with pics all at once. (5)But with it being called “ Deleted Files”, are they all considered the same when deleting and retrieving them?  It seems that Dropbox puts all my uploaded unfiled and un-named singles under camera uploads or phone uploads, (6)which I suppose, they could be considered pre-named Dropbox files (7)Not sure if I can delete pictures as a whole from these (files?) (8)because when opened, the two prenamed dropbox file formats look different than that of a file I named. (9)Dropbox’s Camera uploads and Phone uploads (files?) would make more sense to me if i uploaded photos with a secondary device like a Nikon camera or…..a Cannon. But all my Dropbox photo uploads are sourced from my iPhone camera. So that too is a bit confusing because I don’t choose where my singles go. They just go. Sometimes they go to both prenamed Dropbox (files?) I’ve had Dropbox for 10 years. (10)Looking for answers.