Some of the picks in The Guardian's "Photos that fooled the world" gallery didn't really fool anyone, but it's a great set of famously fraudulent shoops. And some of them sustained durable hoaxes, such as the Cottingley Fairies and the Patterson/Gimlin film.
It's not hard to fathom why those in the darkroom were tempted to play tricks with the technology as soon as they learned that they could. The most obvious motive is the one that fuelled so much early photographic output: PR, or propaganda. It must have seemed only natural to superimpose Lincoln's head on to the body of another man – an enslaver, as irony would have it – if that would yield a more heroic image of the president. The same goes for the portrait of civil war general Ulysses S Grant, depicted at the centre of a military scene that was in fact three scenes combined into one. You want the leader to look as strong and noble as possible. If that means showing him on horseback, while quietly removing the handler who kept the animal under control as the snap was taken, you'll do it – or at least you will if you're in charge of optics for Benito Mussolini.
Previously:
• How a 1937 hoax captured the imagination with giant grasshoppers
• A browser extension that checks web-pages for misleading and hoax images
• Short documentary about the evolution of Photoshop
