That photography is an unreliable witness is certainly not a revelation. How many images have you yourself radically altered in the interest of aesthetics, humor, or plain old deception?
You might, however, find it revelatory to learn that photography has been prevarication-prone nearly from day one of its existence. Faking It: Manipulated Photography Before Photoshop is a fascinating book, and an associated traveling exhibit, in which the Metropolitan Museum of Art’s Mia Fineman presents what may be the first scholarly survey of the history of photographic manipulation prior to digital photography. Fineman traces the history of manipulation from the medium's earliest days* up to the 1990s, when the computer began taking over the medium.
Of Possible Interest
Some pre-xmas hype: