The widespread use of Photoshop in magazines and advertisements has led to concerns about body image and truth in advertising, even inspiring legislators in the UK, France, and Norway to propose mandatory labeling of retouched photos in the past few years. Perhaps computers can be used to solve the problem, as Dartmouth researchers Dr. Henry Farid and Eric Kee have invented a software tool that automatically measures the amount of image alteration on a scale of 1 (very similar) to 5 (very different). The metric forms the rating based on eight different statistics that quantify different aspects of geometric distortion, or image reshaping, and photometric distortion, or image smoothing, and uses a baseline established by human rankings of changes made in over 450 before and after photos. While there's no easy way to implement the technology industry-wide, the researchers hope it could lead to some form of self-regulation, since there's now a simple rating that shows how much an image has been changed.