@Jon and developers :
Solution thought: It might be useful to have a thumbnail - manual override.
Give logged users the option to upload a png for the file. If a thumbnail is
manually uploaded for a specific file, then that file is given priority and
the thumbnail should not be refreshed/re-generated and cached. So if, a user
uploads a thumbnail, it effectively freezes that thumbnail to that clipart.
How can we make this possible?
'Evil mastermind' control tip. So that people don't do nasty
hobbitsssseeesss things like, make a file that is something other than what
the thumbnail says it is, we could have a flagging thing "thumbnail doesn't
match clipart", so that any user can flag dishonesssssst cliparts that will
need to be punisssssssheed. These will get reported to the librarians and
they can hide them. Or give the nassssssty clipartssssss a hiding. Whichever
is more prrrreciousssssss...