title: auto upload and set featured image to wordpress post based on external url
body: <p>I have a music website based on soundcloud api , 
  I have custom post type called albums and each post is a track,
  at the moment i can get all the details i need from soundcloud track as well as the track image url. 
  How can i use this url from soundcloud and make wordpress download that image and set it as the post featured image?</p>
  
  <p>I have tried and searched over the net and couldn't find nothing on how auto upload and publish external featured image.
  Any help would be perfect!</p>
  
  <p>Cheers!</p>