SetEnvIfNoCase Referer      ^(?!http(s)?://(www\.)?(site1.com|site2.com|site3.com|site4.com)|$) not_local_ref=true
<FilesMatch \.(?i:gif|jpe?g|png)$>
Order Deny,Allow
Deny from env=not_local_ref
SetEnvIf not_local_ref true poaching
</FilesMatch>

CustomLog logs/poachers_log   combined   env=poaching