On the picture he wears Knight's Cross that he never received. Simple Iron Cross was never worn around neck. A principal mistake by artist in anyone's eyes who knows just a bit about German military awards.
yeah, the artist has gone a tad overboard here
It looks to be pretty much a straight-up copy of the painting underneath (i spoilertagged it as its quite large), then just adding on a knights cross "for effect", changed his army grey woolen coat to a black leather coat (same with the cap), and generally made it more "menacing".. think SS or Gestapo instead of regular army.
I've looked at a bunch of Hitler pics now (not my favorite past-time...lol), and he is not wearing one in any of them, he is wearing a shirt and tie, with his iron cross on his breast pocket, where it belongs.