RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://www.sitem.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.sitem.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http://sitem.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http://sitem.com/.*$ [NC]
RewriteRule .*\.(jpg|jpeg|gif|png|bmp|swf|dcr)$ http://www.sitem. com/images/logo.gif [R,NC]