1) be sure to put in your environment file (inside your initializer)
2) make sure your form_form has multipart set to true like this:
3) if using passenger, you must put this in config/initializers/paperclip.rb:
Paperclip.options[:image_magick_path] = ‘/opt/local/bin/’
(Make sure your imagemagick binaries are really in /opt/local/bin/. You can type /opt/local/bin/convert -v to check. I would recommend the MacPorts installation of ImageMagick and re-install if you are unsure.)
4) If you’re having trouble getting it to generate thumbnails, try setting Paperclip.options[:log_commands] = true and see what it’s trying to run.