There are several websites to download free wallpaper. DeviantART is one such sites which offers huge amount of wallpapers free of cost. All the wallpapers are divided into various categories and they can be easily accessible.
You’ll find categories on 3 dimensional, Fantasy, OS, iPhone, Technical, Science fiction and many others. Also you can sort popular wallpapers from last few hours.
You can search images by resolution with the help of search box given at the top. There are categories given on the left. Click on category name to browse wallpapers for that category.
Apart from wallpapers, you can find many more things such as browse art work, T-shirts, skins, print shops etc.