The image editing software Photoshop made by Adobe is used by millions of people around the world. It's become so common it is now a verb. And it's hard to imagine a world without it, particularly the fashion world.

"Everything is Photoshopped," said Jessica Coen , editor-in-chief of the online magazine Jezebel. Her site has made a cottage industry of catching fashion editors and advertisers Photoshopping women's bodies in ridiculous ways.

"From the moment a young woman can look at a newsstand, she is looking at these images and these images are saying this is what an attractive woman looks like, and the implicit message, this is what you should look like," Coen says. "But it's actually impossible for any woman to look like most of the images we see in magazines. And that's when we start getting a lot of problems with body image and ultimately god forbid, eating disorders."

While regulators at the Federal Trade Commission do not have a role to policing unrealistic depictions of women's bodies in fashion magazines, they are charged with preventing companies from publishing false or misleading ads. And recently regulators both here and in Europe have begun to ask if some Photoshopped cosmetic ads cross that line. Last week, Proctor and Gamble pulled an ad for Cover Girl Mascara because it used digital editing to enhance the models lashes.

"The ad in question is nothing compared to other ads out there," said Coen. "Particularly if we're going to focus on mascara ads being misleading. The ad that they're pulling, the models eyes are open, and so you can just kind of see the tips of the lash. Women are so used to seeing pictures where models eyes are downcast, and those are the ones that are actually terribly unrealistic."

This year, legislators across Europe are proposing that altered images should be labeled. But Hany Farid, a computer science professor at Dartmouth, thinks that approach might be too blunt. After all, fixing a stray hair or covering up a pimple isn't the same thing as removing 20 pounds or wiping away all the wrinkles from George Clooney's forehead.

So Farid and a graduate student, Eric Kee, tried to build something better.

"Something that distinguished between minor modifications done digitally in things like Photoshop, and more significant digital carving so that both consumers and publishers would have a fair assessment of by how much an image was altered," Farid said.

Farid and his team built a program that rates just how altered digital photographs are.

"What we did is we effectively reverse engineer the types of manipulations that a photo re-toucher would do," Farid said. "So that can be for example enlarging of the breast, sliming of the waist, removing of the wrinkles. So, we mathematically modeled those modifications and now the question is well, how different does the person look given that mathematical measurement?"

Egregious alterations are rated as a 5; small touch-ups a 1.

"We are currently thinking about how we can develop a Photoshop plug-in that would in real time give a photo re-toucher a number, a numeric value, that tells them by how much the image has been moving from its original."

But for now this technology only works if the computer program can see both the original image and the touched up version. Farid and Kee are now trying to teach their program to identify and rate Photoshop images in the wild.