CHECK IF ITS INSTALLED FIRST: from root ssh 

/scripts/checkimagemagick

INSTALLATION 

/scripts/installimagemagick
Installation will take a couple minutes as it will install other packages needed by ImageMagick. After the installation, check that it is installed again and it should state the version. 
/usr/bin/convert --version
It will give you something like: Version: ImageMagick 6.4.8, etc

Imagick Go to WHM -> Software -> Module Installers -> PHP Pecl (manage). On the box below “Install a PHP Pecl” enter “imagick” and click “Install Now” button – that’s all. Restart Apache.

Uninstall: If you decide to uninstall it’s as easy as the installation process: ImageMagick: /scripts/cleanimagemagick Imagick: WHM -> Software -> Module Installers -> PHP Pecl (manage). Click on Uninstall button for Imagick