How to detect similar Images in PHP?

Question

I have many files of a same picture in various resolution, suitable for every devices like mobile, pc, psp etc. Now I am trying to display only unique pictures in the page, but

Answer 1

Well, even thou there are quite a few algorithms to do that, i believe it would still be faster to do that manually. Download all the images feed them into something like windows live photo gallery or any other software which could match similar images. This will take you few hours, but implementing image matching algorithm could take far more. After that you could spend extra time on amending your current system to store everything in a DB. Fix cause of the problem, not it's symptoms.