Quote Originally Posted by edp View Post
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

I think there were cameras with mirror arrangements to flip the image so that it wasn't mirrored. (I realize this is an almost year old post).
The library of congress has been posting lots of tintypes from the civil war on its Flickr site lately, and some of the are the 'right way around'.