The Amazing Spider-Man has been shooting for something like eight years now, and the leaks have been minor. We’re not even completely certain who the villain is, although it’s pretty generally assumed to be The Lizard.
If the picture above is Rhys Ifans, then we can be certain of it. The picture was snapped during New York City location photography on the film; a close look at the skin around the eyes of the person in the mask shows greenish scales. I would imagine this is Dr. Curt Connors at some point in his transformation. It would actually be beyond amazing if we learned that The Lizard is a practical creature in the film, but I seriously doubt that; I imagine Ifan will do some scenes in green scales and then be replaced by a CGI monster.