There is a post here in icon_extras about a community called iconscraper. Not only does the owner, samplebitch, troll the LiveJournal picture feed for icons, (s)he also hotlinks all the images that the feed finds.
I never realized that you could make an RSS feed that requests all the icons that are posted on LJ public posts, whether it be in communities or personal journals. This person has a program that will automatically nab any and all icons that are used and they put them in the community with no care for what the subject matter is. Their mentality is that if you don't want someone stealing personal pictures of yourself, your family, or your children...you don't belong putting them on the Internet and it's your own damn fault so live with it.
There IS a way to prevent this from happening...
1. Open up adminconsole. http://www.livejournal.com/admin/console/
2. For personal Journals, copy/paste the following: set latest_optout yes.
3. For communities, copy/paste the following: set "for" COMMUNITYNAME latest_optout yes.(where it says COMMUNITYNAME, delete that and type in the name of your community)