If your download quota on your website counts or in case it's not very fast anyway, it might be a good idea to disallow others to hotlink (put a direct link on their website) to images of your website. Doing so, every time somebody clicks that hotlink, they're going to use the bandwidth of your hosting server and, depending on the size of the image, may even slow it down.
Fortunately there's a solution for that which is, again, a nice .htaccess trick. Here you'll find a well built article about how to Stop Hotlinking with .htaccess.
