Many a times we come across images where we are stuck into thinking if it is original or photoshopped (fake). Image Error Level Analyzer or simply ELA, is a free web service which helps you in determining if the photo is real or not. So how does it work? Neal Krawetz (Ph.D) explains it nicely:
Error level analysis (ELA) works by intentionally resaving the image at a known error rate, such as 95%, and then computing the difference between the images. If there is virtually no change, then the cell has reached its local minima for error at that quality level. However, if there is a large amount of change, then the pixels are not at their local minima and are effectively original.
You just have to provide an image URL and hit Process. It will then analyze the image and show results instantly after the processing is complete (see screenshot below).
Simple as that! No other actions is required. You can easily compare and tell if the image is original or modified using Photoshop or any other image editor. In our case, the photo above is original.