From The Heretic Knowledge Vault
Art work by Poe that isn't part of the story but features one or more story characters or episodes, intended for use as background on a computer screen. It differs from filler art in two regards. First, it doesn't appear on a particular day as a substitute for a story installment, but rather is updated monthly on a regular basis. Second, it isn't freely available to everybody. Access to wallpaper is one of the perks for donating money to keep the story and the associated business (Caffeine Angel Studios) alive and well. After a particular bit of wallpaper art is no longer current, it may be available for purchase in either hard-copy or electronic form. Most of the main characters have appeared in wallpaper art at one time or another.
Information on donating, as well as a thumbnail of the current month's wallpaper, appears here. You can also click the "Donations" item on this page's sidebar, although the wallpaper sample shown on that link may not be up-to-date.