Good solution for protecting image files in folder

[eluser]esset[/eluser]
This did not work:

Code:

Options -Indexes
Options +FollowSymlinks

RewriteEngine On

# no hot-linking
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain\.se/ [NC]
RewriteCond %{REQUEST_URI} !hotlink\.(gif|png) [NC]
RewriteRule .*\.(gif|jpg|png)$ http://domain.se/hotlink.png [NC]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]