These first two I saw at OMGPosters.
This Batman picture by Raphael Grampa, the source wasn't given, and I haven't done a check to try find it, but I assume it was on his own blog or website. I think I saw it on iFanboy.
I came across this when I did an image search for bird skulls for reference. It's an artist named Kitty Valentine, and she does painting over vintage photos. She had some other cool images as well, so check her out sometime.
These next couple I saw at Bleeding Cool. They were just highlighting this artist named Igor Keiryluk who did some cool alternate Batman type characters.
Next is someone I know I've highlighted here before, Francesco Francavilla. This was from ComicTwart, where they were doing a Silver Surfer week.