RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?your-domain\.tld(/.*)?$ [NC]
RewriteRule \.(gif|jpe?g|png|php|GIF|JPE?G|PNG|PHP)$ - [F]
maybe helpfull
I'm lazy,
what does it do?
if someone create a link directly to the picture or tries to include the picture in his page apache does not allow that and redirects to your front page (your-domain.tld)