Re: How Prevalent is Nude Photography....
It used to happen, but amateur nude photography was a minority hobby, at least among those without their own darkroom.
When I was a student, one year I had a summer vacation job in the Kodak (NZ) slide mounting room. Since it was illegal to send nude pics through the post, Kodak had to pull any boxes of slides containing them and forward the box to the snapper's local cop shop for collection.
This meant that those running the slide mounting machines were expected to spot any such photos and check them in a slide projector. Cue a yell of 'Got one!' and a general stampede in the direction of the projector and screen when anything was found.
However during that summer break (6 or 8 weeks - I forget which) I only remember that happening two or three times on my shift.