"Hotlinking" an image is when a web designer embeds an image tag into his webpage that pulls an image from another site rather than making a copy of the image and hosting it himself. It's lazy, and it "steals" bandwidth that the person hosting the image is paying for. The image appears normal on the hotlinker's site, but it's being loaded from the host's site without any credit being given. That's not cool! And so, I've been forced to protect my images from hotlinking by modifying my .htaccess script.