Check if an Image is Photoshopped or Modified
Error level analysis can help you work out if a photo has been digitally altered. Photos in a jpeg file format actually lose quality each time they are resaved. We can take advantage of this to try and work out if an image has been digitally manipulated.
Tip : Reduce Size of .PNG Images without Losing Quality
Image Forensics : Error Level Analysis
Error level analysis allows you see to see the difference in quality level, represented by brightness. Things which are very bright have been edited most recently, whilst duller parts have been resaved multiple times. This allows you to see not just which parts of the image have been changed, but in what order the changes occurred.
> Go to Image Error Level Analyzer : Link
If the image has had no alterations to it, all parts of the photo will be at the same quality.
Tip : How to Change Size of Animated .GIF Images
4 Responses »
dwindle : I call bullshit. If a photo has been saved at 100% quality, it is identical to the original, bit for bit. Quality is only lost the first time an image has been put into the jpeg format
Debajyoti Das : Not exactly ... when you change parts of a photo the "x-ray" image like the above pic changes... you can easily detect fakes
tim : It pretty much just traces the edges. If you follow the link it says that: "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." That'd make sense if it didn't just trace the edges. The only exception is bottom right where there's a small blotch on the "ELA" version. I tried it with a completely unaltered picture of my own and it lit up just like the example above. It traced bright edges. It do what it says, but I doubt it's very accurate.
Lovelive : @dwindle : If you edit a 100% JPEG, and save again, the save image file contents will not be identical to the result of your edit before saving. @tim : Actually I've tried with another picture and there were no bright edges whatsoever. I think the edges come from an automatic sharpening filter in your camera (it is common), maybe the same for every image with bright edges like this.
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