How can I install the latest Image Magick on RedHat Enterprise 6.6?

On Red Hat systems, ImageMagick is available in the default base package repository so you only need to run:

sudo yum install ImageMagick

Note that the package was built with support for X11 and Gtk+ so it has a huge amount of of dependencies – most of which should only be required for a graphical desktop (and ideally shouldn’t be installed on a head-less server).

For RHEL 6, the version of ImageMagick is 6.5.4.7. If you need functionality that is only available in later versions, you’d be better compiling and installing from source; shoe-horning a binary RPM that was compiled for RHEL 5 wouldn’t make sense. Installing from source would also have the benefit that you could customise it by providing appropriate options to its configure script during the build process.