How do you prevent other sites linking to your attachments?

I don't want sites to steal bandwidth from my server. How do I make it so that if they link to an image, it looks like a dead page, or shows some default image that says, this image that says some sort of warning.

Thanks in advance.

[Erwin]

No hack needed at all - just use a .htaccess file (as long as you are using Apache with mod_rewrite).

.htaccess with the following content, and upload to root directory:

RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://www.yourdomain.com [NC]
RewriteCond %{HTTP_REFERER} !^http://yourdomain.com [NC]
RewriteCond %{HTTP_REFERER} !^http://IPADDRESS [NC]
RewriteRule attachment.php [F]