.htaccess - ReWriteCond

My WordPress installation has generated a nice .htaccess file which prevents my images from being hotlinked. This is really nice, but I need to fetch images from a new bunch of php sites which are running outside my wordpress installation (on the same server)

Now I tried to update my .htaccess file:

    <IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{HTTP_REFERER} !^$
    RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?austrianweddingaward.at    [NC]  
    RewriteBase /
    RewriteRule ^index\.php$ - [L]
    RewriteRule ^_security /wp-content/plugins/password-protect-   wordpress/certificate.txt [QSA,L]
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . /index.php [L]
    </IfModule>

But even when I try to show an image using this line of code: <img src="<?php echo $row->url; ?>" alt="" /> only the nice "?" instead of the image will be shown. (the source of the image is correct:

Image