When a digital imaging system, such as a digital camera or scanner system, performs an image adjustment that affects pixels in a digital photograph, the system stores the original pixel data in a header, tag, or similar informational portion in the resulting digital image file, The original pixel data...http://www.google.de/patents/US20050078191?utm_source=gb-gplus-sharePatent US20050078191 - System and method to allow undoing of certain digital image modifications
