title: Programmatically Add Existing File to Dropzone
body: <p>I'm trying to add an existing image to my dropzone programmatically, using the <a href="https://github.com/enyo/dropzone/wiki/FAQ#how-to-show-files-already-stored-on-server" rel="noreferrer">dropzone.js FAQ</a> as a guide: </p>
  
  <pre><code>// Add the existing image if it's there.
  // headerDropzone is my dropzone (debug shows it as existing and initialized at this point.
  var on_load_header = $( '[name="on_load_header_image"]' ).val();
  var on_load_header_path = $( '[name="on_load_header_image_path"]' ).val();
  
  if ( on_load_header ) {
  
      // Hardcoded size value is just for testing, see my second question below.
      var on_load_header_data = { name: on_load_header, size: 12345 };
  
      // Call the default addedfile event handler
      headerDropzone.options.addedfile.call( headerDropzone, on_load_header_data );
  
      // And optionally show the thumbnail of the file:
      headerDropzone.options. thumbnail.call( headerDropzone, on_load_header_data, on_load_header_path);
  
  }
  </code></pre>
  
  <p>My first problem is that this is just not working.  The addedfile event doesn't fire (or at least the addedfile handler in <code>headerDropzone</code> never fires), same goes for thumbnail.</p>
  
  <p>My second problem/question is: do I have to provide the file size?  I could get it server side, but I'd rather not do it if I don't actually need to.</p>