Movies - particularly comic book movies - go through a lot of concept art before deciding on final designs. They want to stay true to the source material, but adapt it so it doesn't look really dumb when translated to real life and on a movie screen. In the recent The Amazing Spider-Man 2, the designers had their work cut out for them: there are THREE major villains in the film. And the most difficult to translate was undoubtedly The Rhino.
Why? Well, in the comics, Rhino looked like this:
He's basically a buff-as-hell dude in a skintight Rhino outfit. Probably a direct adaptation wouldn't look so great. So what did the designers come up with? Check it out:
Lots of cool concepts! A more mechanized-suit, while still maintaining the basic structure of the original character outline. And for the design actually present in the final film, this is where they landed: