GD or ImageMagick is installed on the webserver by the ISP not you.
(unless you setup the webserver)
Quick way to find out is make a php file and upload it to your webserver.
Code:
Content visible to verified customers only.
When you run the php file from your server you will get a page w/ all your server settings.
Search for
GD Support if not found search for
Imagemagick
This will tell you what is enabled or not and what Ver.