Photoshop is an amazing tool for altering reality, but it’s only really great when you’re aware of its effects. Here are several tips for detecting a Photoshopped images and earning your digital forensics merit badge.
Using Your Eyes
When it comes to detecting anomalies in a photo, your eyes are really your best asset. Without practice, they’ll fool you, but you can train yourself to start noticing the little imperfections and oddities that’ll point right to a manipulated photograph. For solely educational purposes, I gave Mark Zuckerberg a new face to illustrate a few fake detection points. You can see both images above — the original is on the left and the altered version is on the right (if that isn’t very obvious already).
Most faces are pretty dynamic, topographically speaking, and the eyes are a great example. Although eyes can sometimes look a little flat in a photo (thanks to good lighting and probably some help from Photoshop in post), you’ll generally find a few areas in a photo that picked up shadows. If this is the case, try to determine if the shadows are realistic for the face. If you look at the right eye in both of the Zuckerberg images, you’ll see that the shadow to the right of it has changed quite a bit. The original shadow did not work with the original eye, so I tried to correct it. Nonetheless, you can see that they eye isn’t sinking in as much as the shadow. This could’ve been helped with a little warping and painting by hand, but there’s only so much you can do. Poor perspective is always a good indicator of a fake.
Image analysis software can help you detect unrealistic characteristics of an image, but this software is generally pretty expensive. Instead, here are two tips for fake detection with a free online tool and Photoshop. (Yes, Photoshop is expensive too, but you probably already have it and you can use other image editing apps instead.)
Image Error Level Analysis is a tool that creates a heat map-like image out of a JPEG that shows you the highest points of compression. Excessively Photoshopped images may contain JPEG parts that have been saved over and over again. This little tool will, in theory, detect those parts and highlight them for you. Personally, I haven’t had much luck, and it seemed to think my Zuckerberg makeover was generally less altered (as best as I can interpret the results), but your mileage may vary.
Alternatively, another way to catch this is boosting the saturation like crazy. Not only does this start to show areas of JPEG compression, but it’ll accentuate the tonal and colour differences in the photo and make them easier to detect.
There are still tons of other ways to notice imperfections. If you’ve got any good tips on detecting a Photoshop fake, you know where to post them (hint: the comments).