Validate that a file is a picture in PHP

Question

If a file is uploaded to the server, is there a way using PHP, to make sure that it\'s actually a picture and not just a file with a .jpg or .gif extension?

Answer 1

Using (part) of the GD library.

PHP: GD - Manual

array getimagesize ( string $filename [, array &$imageinfo ] )

The first element of the array will be 0 if there is no image. PHP: getimagesize

If you don't have GD installed (most of the time you will), you can read the file header as Shane mentioned.

EDIT: Actually, as Neal pointed out in the comments, the GD library is not even required to use this function. So use it.