Bug#795708: Metadata_block_picture screenshots

[Andreas Olsson]

To better illustrate, let me share screenshots, comparing a .ogg
containing a Metadata_block_picture to one without.

  Without Metadata_block_picture: https://owncloud.arrakis.se/public.php?service=files&t=ca3e282753dc5a2c09e5373898028ca3

  With Metadata_block_picture: https://owncloud.arrakis.se/public.php?service=files&t=0343594e49b9407e303f61465dcb963e

// Andreas