image attachment in mail with rails3

[amruby]

yes this will send one mail with attachment of image.png. But when i open or download that image, that is empty.?

imageurl = https://chart.googleapis.com/chart?chs=150x150&cht=qr&chl=5&choe=UTF-8

require 'open-uri'

class UserMailer < ActionMailer::Base

  default :from => "ma...@example.com"

  

  def welcome_email(imageurl,mailid)

    attachments['QR.png'] = {:mime_type => 'image/png',

                                     :content => open(URI.parse(imageURL))}

    mail(:to => mailid,

    :subject => "Code",

    :body => "Code")

  end

end

Thanks 

vishnu