paperclip processors

style.rb

has_attached_file :main, :styles => { :grid => "250x390>", 
                                        :detail => "400x600>", 
                                        :thumb => "75x75#", 
                                        :trans => { :processors => [:trans_to_dark] }
                                        },
                                        :default_url => "/images/missing.png",
                                        :storage => :s3,
                                        :s3_credentials => "#{RAILS_ROOT}/config/s3.yml",
                                        :bucket => "mybuck",
                                        :path => "product_images/:id/main/:style.:extension"