Upload profile image (using image url) on Twitter. (Thanks a lot, @hanachin_)

update_profile_img.rb

#!/usr/bin/env ruby
#-*- coding: utf-8 -*-
require 'twitter'
require 'open-uri'
require 'tempfile'

Twitter.configure do |config|
  config.consumer_key = YOUR_CONSUMER_KEY
  config.consumer_secret = YOUR_CONSUMER_SECRET
  config.oauth_token = YOUR_OAUTH_TOKEN
  config.oauth_token_secret = YOUR_TOKEN_SECRET
end

img_url = "http://a0.twimg.com/profile_images/2935155837/1d457cc612260bbd7ace398083330886_normal.jpeg"

img = open(img_url)

#make tmp file.
tempfile = Tempfile.open('icon'){|file| file.write img.read; file}

#update
Twitter.update_profile_image(open(tempfile.path))