RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?deleonism.org [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?crimsonbird.com [NC]
RewriteRule \.(jpg|gif)$ - [NC,F,L]