Compare Images PHP Class
This PHP Class compares two images and returns a number representing how similar they are. It is capable to tell if two pictures are similar even if they have different sizes or aspect ratio. Smaller number means the images are more similar. Numbers more than 10 means they are most likely not the same image.
Example #2: Different size. And aspect ratio. Number you get: 4
Example #3: Different light and contrast. Number you get: 1
Example #4: Exactly the same image. Number you get: 0
Example #5: Completely different image. Number you get: 25