Any ideas about this pressed-metal (?) frame, please ...

Hi. This came home from a yard sale south of Sydney yesterday. It was apparently bought in England. There is mirror under the decoration at the top. I think what remains of the "picture" might be pencil and ink. It's 17 x 9 inches and the hanger looks to be a later addition. I've not seen such a thing before but maybe someone will recognise it instantly and tell a bit about it. Age, origin, what for, why ... all that sort of thing. I've no idea what the metal is. Thanks very much.

 

Interesting and pretty old looking....backing looks to be wood, but I can’t tell if the metal on the front is copper or maybe brass??? Maybe there was meant to be a mirror in front of what you see as a possible picture? (Although it does look like a youth profile on the right of it)...