Watermarking Hotlinked Images

Content of the .htaccess File placed in the Playground Root Directory.

RewriteEngine on
RewriteCond %{HTTP_REFERER} !^http://isaka\.dyndns\.org/ [NC]
RewriteCond %{HTTP_REFERER} !^https://isaka\.dyndns\.org/ [NC]
RewriteCond %{HTTP_REFERER} !^https://yuumura\.dyndns\.org/ [NC]
RewriteCond %{HTTP_REFERER} !^http://yuumura/ [NC]
RewriteCond %{HTTP_REFERER} !^https://yuumura/ [NC]
RewriteCond %{HTTP_REFERER} !^$
RewriteRule ^(.*)/([^/]*\.(gif|png|jpg)) /vhosts/playground/watermark/watermark.php?src=/vhosts/playground/$1/$2 [L]