This is needed for OwnCloud. This article has a good description of the install process….
http://www.cyberciti.biz/faq/ubuntu-linux-install-or-add-php-gd-support-to-apache/
Commands for installing GD
Install GD via apt-get and then restart Apache
sudo apt-get install php5-gd
/etc/init.d/apache2 restart
Verify GD is Loaded…
$ php5 -m | grep -i gd
Output should be “gd”
test.php
Alternatively create a test.php file using this code snippet…
<?php phpinfo(); ?>
Navigate to the page and look to see if GD works. Might be good to remove test.php after using it as it might be a security hole, not sure about this myself, but just a thought.