Do you need PHP support for GD?
First you need to be sure this module is not already installed, on a shell window run the following command:
Linux console
$ rpm -qa | grep php
If you have something like this:
Linux console
php-gd-5.1.6-3.fc6
The module is already installed, otherwise run the following command:
Linux console
yum -y install php-gd
Voila!
