For those who use Apache 2.x, this is a nice trick to keep people from hotlinking your images. I’ve seen a few variants of it, but this one I picked up most recently from a slashdot comment, of all places.
Make sure you have enabled mod_rewrite, then add this in your
.htaccess file for any directory with images in it:
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to redirect to an awful image, or use my own personal variant:
1 2 3 4
which doesn’t return anything if someone else hotlinks your images. If they like your images enough, they can like them enough to save a copy on their own webserver.