Take the case of "Gulf Wars Episode II: Clone of the Attack," one of the most widely circulated Photoshop images on the Internet. This doctored "Star Wars" movie poster was originally published last December in Mad magazine. But when it leaked to the Internet, several new variations appeared. Most of the people who see this image have no idea it came from Mad; since images like these began their lives as hybrids of images that we consider public domain (like the president's face), manipulators feel no qualms about appropriating them further. A Photoshopper thus faces an odd paradox of fame: The more popular his or her image becomes, the less likely viewers will care where it came from (in compiling our own gallery, tracing down the original artist became virtually impossible).

Web sites such as Fark and Freaking News have popped up to encourage participation in the Photoshop revolution. Offering little more than a list of user-provided news links, these sites provide daily "Photoshopping contests" that urge visitors to create new images according to a specific categories, or to combine two disparate images. It's digital riffing off a recognizable visual theme. To help potential Photoshoppers get started, both sites offer tutorials and skill-improvement techniques.

Henry Jenkins, director of the Comparative Media Studies program at MIT, has tracked the popular use of Photoshop and says that people started using Photoshop as a tool for critical commentary almost as soon as the program became available in early 1990. "The question is not when did it start, it's the scale. We're seeing more and more every year, with a real increase during this election cycle. Both sides are feeling enormous anger; they want to be involved and express their political views."

He adds that Photoshop allows large groups of individuals to communicate with other large groups of individuals on a topic that they may not have previously felt comfortable talking about. "Like political cartoons, Photoshop images are symbolic speech."

Despite Adobe's tireless reminders that trademarks are not to be used as verbs or nouns, and that trademarks must never be used as slang terms, over the past few years, Photoshop has broken free of the jargony domain of designers and photographers and has joined the lingo of the people. Urban Dictionary, an online slang dictionary that asks users to submit definitions, defines "photoshop" as "A program made by Adobe used to manipulate images. Also a term for an image manipulated with the software, which is usually a combination of two or more unrelated images (as in, Dude, he photoshopped Hitler's face onto Clinton's body! That is totally ninja!)."

Steven Heller, a design critic and historian, and co-author of "The Designer's Guide to Astounding Photoshop Effects," points out that the concept itself is not new: "Image manipulation is a historically venerable thing to do. It goes back to the 18th and 19th centuries, when paintings were manipulated in such a way, they would take court paintings and paint over them in such fashion."

But won't these images eventually wear thin? Aren't we getting tired of seeing, for example, George W. Bush kissing Tony Blair, or John Kerry dolled up like Herman Munster? "It used to be that you saw something done in Photoshop and you'd immediately forward it, for the sheer novelty of it," says MIT's Jenkins. "Now people are more discriminating. In the same way that we don't cut out every political cartoon and stick it on our refrigerators, we no longer forward every Photoshop image we receive. But when the image clicks, they can both be powerful ideas about the political moment."

Recent Stories