For decades, JFK conspiracy theorists have claimed this photo of Lee Harvey Oswald holding a rifle and a Marxist newspaper was a fake. Dartmouth College digital forensics expert Hany Farid built a 3-D model of Oswald's head and proved otherwise.
Actually, Farid says you can't prove a photo is real, but he did knock down one of the main arguments that the photo was faked: People claim the light sources hitting Oswald's face are all wrong, proving it's a paste-up job. But Farid painstaking mapped all the light sources in the picture and compared them against his model of Oswald's head. According to the Union Leader:
He used a computer program Facegen, to build a virtual 3D model of Oswald's head. Once that was completed, he added in the background features of the photo. Through a series of computations, he figured out where the camera had to be, the trajectory of the sun and where Oswald was in relation to the camera.
After that, it was many a sleepless night Farid said, trying to match exactly the shadows to those pictured in the photo...
Farid said given the technology available 46 years ago, there is no way someone would have been able to get the internal and external elements of the photo just right in order to fabricate not only the one photo, but two others in the series.