For you wallers this might be something intoresting you might want to start doing.
Ways to protect your wallpapers from getting ripped off the site.
Brand them this means put your username copyright and any info at the bottom of the wallpaper.
WaterMark Make a little image as your watermark then put it at the bottom of the wallpaper with a blending property that will make it visible but not at a glance. you have to look for it.
PhotoshopWatermark For those that use Photoshop you can put a vertal watermark on your work this will keep people from ripping you off
Report ripper to their host you can find out what host someone is using ether by DNS lookup or a whois lookup on Register.com
I hope some of these help you out