Attribution for background image in gdm-config

[jdreed]

The picture of Killian is from Flickr ( http://www.flickr.com/photos/22240293@N05/3930252680/), available under CC-BY-2.0. We attribute it in the copyright file, but it's unclear if that's good enough to satisfy the terms of the license? We could trivially add the author's name with GIMP or something.

(If someone can authoritatively say it's good enough in the copyright file, then close this ticket).

[jdreed]

Quoth  http://creativecommons.org/licenses/by/2.0/legalcode:

Such credit may be implemented in any reasonable manner; provided, however, that in the case of a Derivative Work or Collective Work, at a minimum such credit will appear where any other comparable authorship credit appears and in a manner at least as prominent as such other comparable authorship credit.