For installing ImageMagick on a Cpanel server manually you will need to take the following steps:

1. Log into your server as root
2. Create a new directory as below :
   mkdir /home/cpimins
3. cd /home/cpimins
4. wget http://layer1.cpanel.net/magick.tar.gz
5. tar zxvf magick.tar.gz
6. cd magick
7. /scripts/installrpm ImageMagick
8. /scripts/installrpm ImageMagick-devel
9. sh ./install

Or you can install ImageMagick and ImageMagic-devel through WHM by taking the following steps:

1. Login to WHM https://<ip_address>:2087.
2. Go to 'Main >> Software >> Install a RPM'.
3. Select to install ImageMagick and ImageMagic-devel.