How can I reduce the quality of an uploading image using Paperclip?

I am running Ruby on Rails 3 and I would like to reduce the quality of an uploading image using the Paperclip plugin/gem. How can I do that?

At this time in开发者_高级运维 my model file I have:

  has_attached_file :avatar, 
    :styles      => {
      :thumb     => ["50x50#",   :jpg],
      :medium    => ["250x250#", :jpg],
      :original  => ["600x600#", :jpg] }

that will convert images in to the .jpg format and will set dimensions.

Try using convert_options.

has_attached_file :avatar, 
                  :styles          => { :thumb => '50x50#' },
                  :convert_options => { :thumb => '-quality 80' }

From the paperclip wiki, there's an option for quality:

class User < ActiveRecord::Base
  has_attached_file :photo,
                    :styles => {
                      :small => {
                        :geometry => '38x38#',
                        :quality => 40,
                        :format => 'JPG'
                      },
                      :medium => {
                        :geometry => '92x92#',
                        :quality => 50
                      }
end

As James says, once you figure out the correct arguments to pass to ImageMagick's convert by experimenting on the command line, you can pass these in to Paperclip through the convert_options option as in James' example.

If you have multiple arguments, pass them in as an array. Here's an example which I laboured over for a while:

:convert_options => {:medium => ["-shave", "2x2", "-background", "white", 
                                 "-gravity", "center", "-extent", 
                                 "530x322", "+repage"],
                     :small  => ["-shave", "1x1"] }

Except -quality, the -strip option of ImageMagick can remove all profile and other fluff from the image which may reduce more size

has_attached_file :photo,
  :styles => {
  :thumb => "100x100#" },
  :convert_options => {
  :thumb => "-quality 75 -strip" }