In my other post I have now belatedly added the link to the Pictures Gallery area, makes it easier to find. It is definitely different from the Digital Photography area. For instance, the POTD thread is meant to be a showcase of one's best images (one per day) while in the Pictures Gallery there are many threads where people can post as many shots at any time as they want of their meals, their pets, their cars, etc.
I think many of us photographers who hang out in the Digital Photography section tend to create our own wallpapers from our own images, rather than use stock images or other people's. I have had people on MR ask me for higher-rez versions of something I've posted or if it would be OK to use one of my images for their wallpaper. While it's flattering to be asked, personally I prefer to have only my own iPhones, iPads and computers displaying unique images that I have shot.