Image forensics company Fourandsix set up an interesting page called “Photo Tampering throughout History“. It’s an interesting timeline of famous photo manipulations, going as far back as the 1860s — the above left image of General Grant was found by the Library of Congress to actually be a composite of three separate photos! Pretty good for not having access to Photoshop, eh?
If you’ve ever wondered just how much editing goes into a particular photograph, there’s now a super easy way to find out for yourself. Image Error Level Analyser is a simple web application that takes a URL to a JPEG photo and returns an image showing differing “error levels” in the image. Here’s an example they give:
After submitting the image on the left, they return the one on the right.
Error level analysis shows differing error levels throughout this image, strongly suggesting some form of digital manipulation. Areas to note are the lips and shirt, as well as the eyes. All are at significantly different error levels than their surroundings. Presumably, colours have been altered and areas brightened.
Thus, you can now investigate any JPEG you find on the Internet to see roughly how much the photograph has been edited or manipulated. The app even gives you a permalink to the resulting image comparison. Try it out, and post your permalinks in the comments to share your findings with us!
Update: Here’s an interesting article by Wired on how researchers use this technique.
