gistfile1.rbx

class Photo < ActiveRecord::Base
  belongs_to :user
  has_attached_file :file,
                    :styles => {
                      :bigger => "73x73>",
                      :normal => "48x48>",
                      :mini   => "24x24>",
                      :flash_badge => '240x180!'
                    },
                    :storage => :s3,
                    :s3_credentials => "#{RAILS_ROOT}/config/amazon_s3.yml",
                    :bucket => 'twitter_production',
                    :path => ":class/#{user_id}/:id/:style.:extension"

  validates_attachment_presence :file
  validates_attachment_size :file, :less_than => 700.kilobytes
  validates_attachment_content_type :file, :content_type => ['image/jpeg', 'image/png', 'image/gif']

end