Drupal 8 - Render Thumbnail Image (Managed File)(SOLVED)

I'm working with Beta7 version of Drupal 8 and the managed file upload is only rendering a file icon instead of the thumbnail image of the uploaded file. There doesn't seem to be any documentation about what the procedure needs to be to get a thumbnail image of the uploaded file to render. Even using the managed file theme on the form didn't help. It still just shows a file icon. Anyone know what the new procedure needs to be to get a rendered thumbnail of the uploaded file?

RE: SOLVED

Apparently the previous code which provided this ability was patched out of the core file module back on May 14, 2014 while they were working on integrating twig. Although the file widget does thumbnails, its not suitable for the use-case I'm dealing with as its more for content entities. Three lines of code did the trick.