[CentOS] httpd .htaccess rewrite for images

Hello, I'm running httpd on a Centos 5.3 machine. I'm trying to use .htaccess to disable direct linking to site images. I've got the following rewrite rule, the domain is test.example.com which is at /var/www/test.example.com under which is a directory called images.

RewriteEngine on RewriteCond %{HTTP_REFERER} !^$ RewriteCond %{HTTP_REFERER} !^http://(test%5C.)?example.com/.*$ [NC] RewriteRule .(jpg|gif)$ - [F]

In my httpd virtual host directive i have:

alias /images "/var/www/test.example.com/images" <Directory "/var/www/test.example.com/images"> Options None AllowOverride None order allow,deny Allow from all </Directory>

Comments appreciated. Thanks. Dave.