Ok. Searching for files is a serious weakness in OS X.
If I want to search for a file that's a certain size... SOL
If I want to search for files that are .BMP only... SOL
Granted I could do a search in spotlight for kind:images and then switch to list view, sort by kind, and then manually select only the BMPs but that's stupid. I should at least be able to search for "Kind:bmp"
I'm in absolute awe that I can't just do a search of a specific location, for a specific file type or attribute, select all, & delete.
Update: I just found out that searching for "kind:bitmap" works whereas "kind:bmp" doesn't. (Stupid)
I'm going to let someone else handle this who does searches more than I do... it's not something I do that often...
BUT... I think you can do everything you list... I opened up spotlight and typed in .bmp and WHAM... there they were.
I also opened up Finder and set the spotlight search box criteria to SIZE and WHAM... there it was.
So my guess is that all you say if more than possible... and hopefully someone will be along soon who can explain it better. - JamesJM