Check out existing wallpapers to see what we're into. For starters, we typically prefer simple, pleasing photographs of nature with a shallow depth of field. Wallpapers that are less busy, have a single focal point, and are generally more out of focus near the edges are more likely to be chosen.

Also keep in mind the desktop environment: elementary OS has a transparent panel at the top, so wallpapers with less-bright, lower-contrast top areas will look best. If the area under the panel is too bright or high-contrast, it automatically get masked with a dark translucent overlay. We also use a small white dock at the bottom, and icons hang over the top edge of the dock. Wallpapers with less-busy, lower contrast areas near the bottom will look better.