title: how to get and use url with UIImagePickerController
body: <p>I use UIImagePickerController to select an image. i get following keys from info class.</p>
  
  <pre><code>UIImagePickerControllerOriginalImage = MonoTouch.UIKit.UIImage    
  UIImagePickerControllerReferenceURL = assets-library://asset/asset.PNG?id=1000000001&amp;ext=PNG    
  UIImagePickerControllerMediaType = public.image
  </code></pre>
  
  <p>i can not use reference url to use this image later. what can i do to use this reference?</p>
  
  <pre><code>imageURL = e.Info[new NSString ("UIImagePickerControllerReferenceURL")].ToString ();
  
  imageBackground = UIImage.FromFile (imageURL);
  </code></pre>