Using Mac ports
If you have an existing ImageMagick installed, you will get this error:
To remove the old version, try:
—> Deactivating ImageMagick @6.4.3-6_0+q16
—> Uninstalling ImageMagick @6.4.3-6_0+q16
USING IMAGEMAGICK WITH PAPERCLIP WITH PASSENGER:
set this in config/initializers/paperclip.rb