Or, to prevent ANYONE from linking to your images...
RewriteEngine on
RewriteOptions inherit
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://.*YOURDOMAIN/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://.*YOURDOMAIN:80/.*$ [NC]
RewriteRule .*[Jj][Pp][Gg]$|.*[Gg][Ii][Ff]$ http://SOMEURL
Be sure to replace YOURDOMAIN with your actual domain name, and replace SOMEURL with the URL that you want the surfer to go to should they actually click on the red X on the hot linkers site!