This 1839 photograph by Hippolyte Bayard, a Frenchman, is claimed to be the earliest instance of photographic fakery. Frustrated by his lack of recognition, he took a photo of himself posed as a corpse and wrote on the back of the photo: "The Government, which has supported A Daguerre more than is necessary, declared itself unable to do anything for M. Bayard, and the unhappy man threw himself into the water in despair."

This 1857 picture by Oscar Rejlander claims to show a street urchin tossing chestnuts. The problem? According to Paul Martin Lester, stopping a moving object in mid-air was a technical feat impossible with the slow film and lenses in use at that time.

...including this rocky outcropping. This photo, known as "Home of the Rebel Sharpshooter", almost definitely does not feature a sharpshooter, as the gun next to him his not a sharpshooter's rifle.

Alexander Gardner's Photographic Sketch Book of the Civil War is perhaps the most famous collection of Civil War photography. This photo claims to show the aftermath of the Battle of Gettysburg, but in 1961, Frederic Ray, art director of the Civil War Times, noticed that this body appeared more than once in the collection...(see next image)

In 2009, the New York Times commissioned the photographer Edgar Martins to travel around Detroit and take pictures for a slide show called "Ruins of the Second Gilded Age." Some sharp-eyed readers on Metafilter spotted the fact that the images had been altered, and the Times was forced to take down the slide show and post an apology.