Originally Posted by Lycanthrope

joechip is partly correct...

However, make sure you allow null referrers if you want the spiders to find your images, otherwise they'll redirect per your hotlink instructions.

This says, allow null referrers and requests from my domain only to display images. Send all other requests to hotlink.html:

RewriteEngine On
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?yourdomain.com.*$ [NC]
RewriteRule .*[Jj][Pp][Gg]$|.*[Jj][Pp][Ee][Gg]$|.*[Gg][Ii][Ff]$ http://www.yourdomain.com/hotlink.html