Regardless of it’s authenticity, is is, much like the “Shroud of Turin” pretty interesting.
It might also be interesting to put a picture of the “Mandilion” or facial portion of the Shroud next to or superimposed over this mysterious (if not somewhat dubious) image for comparison.
Producing such raised / “3-D” images on sheet metal is a very ancient and fairly simple process which can be accomplished with hand tools. IIRC it’s called “Repousse’”.
http://en.wikipedia.org/wiki/Repoussé_and_chasing
I’ve done it; how complicated can it be?