RewriteEngine on
# Remove the following line if you want to block blank referrer too
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http(s)?://(.+\.)?example.com [NC]
RewriteRule \.(jpg|jpeg|png|gif|bmp)$ - [NC,F,L]
# If you want to display a "blocked" banner in place of the hotlinked image,
# replace the above rule with:
# RewriteRule \.(jpg|jpeg|png|gif|bmp) http://example.com/blocked.png [R,L]
