Add dark background with image

The image is taken from

  http://commons.wikimedia.org/wiki/File:Blassenstein_Erlauftal_mit_Nebel_02_Panorama.JPG

By Uoaei1 (Own work) CC-BY-SA-3.0
(http://creativecommons.org/licenses/by-sa/3.0), via Wikimedia Commons.