So for image manipulation, you need imagemagick, and rMagick, which is the ruby layered on top of it. However, I had trouble installed rMagick because it complained about, first imagemagick not being installed (when it was), and then about missing libraries.
I didn't want two copies of the same app floating around on my system, by installing the tarball, so I found this large (and helpful) explanation.
Usually this problem occurs when installing RMagick over a version of ImageMagick/GraphicsMagick ("xMagick") from a binary package such as an .rpm or .deb. The problem occurs because the package installs just xMagick but omits one (or all) of the libraries that it uses, such as the FreeType library or the XML parsing library. Or the libraries are installed but not the header files that RMagick needs.
So I had to look for the gem, which for me is under
And read the config.log file. I found that I was missing "libMagick.so" and "libBZ2.so" I had both of these installed, but I used YUM's "provides" command to find the packaged I needed that provided those libraries. I found the development packages and installed those.
yum provides libMagick
yum install libMagick-devel
yum provides libbz2
yum install libbz2-devel
gem install rmagick