try this

[Anon]

Try this:
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^{http://www.yourdomain.com} [NC]
RewriteCond %{HTTP_REFERER} !^{http://www.yourdomain.com} [NC]
RewriteRule .*.(gif|GIF|jpg|JPG|mpg|MPG|Mpeg|mpeg|MPEG|rm|RM)$ http://www.yourdomain.com [R,L]

It will protect Gif, JPG, MPG, MPEG, and RM files

[warmwind]

Sweet as!

I take it that the two
RewriteCond %{HTTP_REFERER} !^{http://www.yourdomain.com} [NC]
RewriteCond %{HTTP_REFERER} !^{http://www.yourdomain.com} [NC]

..are for different domains?