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Image::Magick is not related to GD, so that information wouldn't be indicative of anything.

As for GD, having GD as a yum module isn't the same as compiling GD into  PHP as a PHP extension. Have you checked in your phpinfo page if GD is  listed?

If it isn't, then if you have access to compile it, you can run  /scripts/easyapache or WHM > EasyApache (Apache Update) to add GD  extension.