Ubuntu default wallpapers are selected after an open community contest, where users submit wallpapers, wallpapers voted and landed in Ubuntu.
The Flickr-based submission contest ended on August 28th 2012, and, after the voting and selection process, the background pack has officially landed in Ubuntu 12.10.
Green plant with natural proportions, setting sun versus a red-ish flower, interesting nature snapshots, geometric patterns, abstract quetzal, come to deliver a professional selection suitable for numerous tastes.