It's a small contact print

a scrap of paper

It's a tintype. But yes, an obscenely expensive one.

This amused me:

The tintype format was an early type of photography which used metal plates to create reverse images, and the photograph led to the mistaken belief that the outlaw was left handed. This is why a 1958 film about his life, starring Paul Newman, was entitled The Left Handed Gun

http://www.guardian.co.uk/artanddesi...hotograph-sold