Involved picking three DeviantArt images and posting them in a comment to the contest. I think they had to be similar in color or something, and you had to have a description about them of sorts? I looked in the Contest category all the way back to 2010 and couldn't find it, although I think it was only 2-3 years back. Good chance it wasn't an official DA contest. I entered it but now I forget the description I had and want to look at other entries as well.