Day 14 - Current (or most recent) comic-themed wallpaper.
Two of the ones I use a lot are the Supernova/Booster Gold reveal on the 52 cover and the Brightest Day cover spread with all the returned characters on their thrones. Just because of the epicness to them and the fact I adored those characters (Booster and Max.)I also had a Spider-man family pic with Spider-Girl (Mayday Parker) I liked to reuse. I think for Fathers' Day last year I forgot to take off the cover for one of the Starro issues which had a Starro controled Rip trying to kill Booster. Awkward.