Wallhaven - Wallpaper site that contains wallpapers for any possible theme and topic. The site is currently in alpha stage, so, after it reaches beta, all of the current users and posted wallpapers will be reseted and site will start over. Registration is required for full content.
DeviantArt - "Parents need to know that this arts-based online community is a great space for teens to showcase their artistic endeavors -- but it’s not for young kids. Over 100 million works of art -- from literature to photography to manga and body art -- can be found throughout the gallery space. Users can browse, comment, critique, and build their fan base. There’s even the potential to buy and sell art. The work featured in members’ galleries varies in quality -- and appropriateness. Parents should be cautioned that there are some images that may be offensive, including violent imagery, mild nudity, and provocative poses. Members can update their status, comment, send public or private messages, participate in art contests, and chat live in hundreds of different-- unmoderated -- chat rooms."
Ewallpapers - "Top Desktop Wallpapers, Free download in High Quality Resolutions for Iphone, IPad, Full Screen and dual monitor"