參考：
http://rmagick.rubyforge.org/install-faq.html
How do I install RMagick on Microsoft Windows?
Use the rmagick-win32 gem. This gem is bundled with a a copy of the ImageMagick Windows installer so you don't need to download your own copy. Download the rmagick-win32 gem from the RMagick project page on RubyForge, unzip it into a temporary directory, and follow the instructions in the README.html file you'll find in the package. (This gem is not for use with the Cygwin environment for Windows. See this question.)
值得一提的是：RMagick_×××.exe和RMagick.gem是都需要安裝的。
Other Info
ImageMagick sourceforge page：
http://sourceforge.net/project/showfiles.php?group_id=24099&package_id=47692&release_id=596046
fleximage getstart：
http://github.com/Squeegy/fleximage/wikis/gettingstarted
fleximage download page：
http://github.com/Squeegy/fleximage/wikis/installingtheplugin