What is the best way to determine whether or not a file is an image in PHP?

Question

I have a sever which people can upload files to. The problem is that some of the filenames are mangled (dont have any extension) and so I cannot immediately determine file type.

Answer 1

Look at image magic identify. http://www.imagemagick.org/script/identify.php

The php wrapper is here: http://www.php.net/manual/en/function.imagick-identifyimage.php

Or if you just want to validate that it's an image (and don't care about the meta data): http://www.php.net/manual/en/function.imagick-valid.php