Ach Otto Otto! Du Schoene Mann!
The picture is from a 1931 picture book Der Maenliche Koerper that I own. It's 59 pictures by one Professor Eugen Matthias of a single athlete all shot in kunstliche Art Deco lighting. I don't know if his name was Otto, but I think Siegfried Arno was singing to someone like him. The text of the book is quotations from Nietzche and banging on about ancient Greece. What the book is really about is a hot young guy willing to drop his skivvies and pose for the professor's camera. Oh Baby!
Here are some other boys named Otto:
It's been one of those days.