title: Android Intent Share using external image url
body: <p>I couldn't help noticing that all examples of sharing images with Intent use locally stored files. 
  Whenever I try to use a external url, facebook, twitter etc. gives me a toast saying "One or more media items could be not be added".</p>
  
  <p>Do i have to store a copy of the image locally?If yes, how do i do that?</p>