I followed the installation of RMagick for OSX: http://rmagick.rubyforge.org/install-faq.html#osx
I have done the
Struggled with this problem for a while, and the fix below (copied from this SO answer solved the issue (specifically the section about symbolic links).
rmagick has a problem working with imagemagick (>= 6.8.0-10) from homebrew.
You can either
update rmagick gem by
bundle update rmagick
or manually symbol link some dylib to make it work:
$ cd "`Magick-config --prefix`lib"
$ ln -s libMagick++-Q16.7.dylib libMagick++.dylib
$ ln -s libMagickCore-Q16.7.dylib libMagickCore.dylib
$ ln -s libMagickWand-Q16.7.dylib libMagickWand.dylib
After that gem install rmagick should work.
Check the discussion about this in https://github.com/Homebrew/homebrew/issues/16625