http://hurtyelbow.typepad.com/hurtyelbow/2006/09/slimming_photos.html

The paparazzi has been exploiting this slimming feature and other HP image effects for months on their photos of Kate Moss (Cocaine Residue Effect), Pete Doherty (Random Syringe Effect), and Kate Bosworth (Nipple Slip Effect).

This is a real thing... though the picture is faked.