We've created a new sub-forum in the Picture Gallery for desktops images, wallpapers, lock screens, themes, and icons. It's called UI Customization. These threads have been popular over time, and by gathering them into one place we hope to make the topics more systematic and make it easier for interested members to find images. We've made a set of prefixes and set up some guidelines, which you can read more about in the forum sticky. Enjoy!