LJ has a feed for the latest images posted publicly here: http://www.livejournal.com/stats/la
Someone has set up a community with an automatic script to scrape off [link] any image that is posted publicly that meets LJ icon requirements and post them to that community (iconscraper). The posts in the community hotlink the original source of the images.
However, you can opt out your journal, and prevent images you post publicly in your journal from being included in iconscraper and similar scripts that are scraping from the latest-img LJ feature. All you have to do is opt out of the latest-img thing.
Make sure you're logged into LJ as your journal. Go to the Admin Console at http://www.livejournal.com/admin/consol
I have opted out for adogs_breakfast, so images you post to this community will not be hotlinked. Please know that you can post images here safely.
If you are also a community maintainer, I strongly suggest you do the same to protect the members of your community/ies. To protect a community, go to the admin console link above and type set for communityname latest_optout yes and click on the execute button. If you maintain more than one community, you will need to do this for each community, replacing communityname each time.
I have also opted out for sga_lazyfans, just FYI. Icon away!