[FIXED] How does comparing images through md5 work?

Issue

Does this method compare the pixel values of the images? I'm guessing it won't work because they are different sizes from each other but what if they are identical, but in different formats? For example, I took a screenshot and saved as a .jpg and another and saved as a .gif.

Solution

An MD5 hash is of the actual binary data, so different formats will have completely different binary data.

so for MD5 hashes to match, they must be identical files. (There are exceptions in fringe cases.)

This is actually one way forensic law enforcement finds data it deems as contraband. (in reference to images)

Answered By - jondavidjohn

Answer Checked By - Marie Seifert (PHPFixing Admin)