Someone

SetEnvIfNoCase Request_URI  ".(jpg|jpeg|png|gif)"	poach_attempt
SetEnvIfNoCase Referer      ^(http(s)?://(www\.)?(site2.com|site3.com|site4.com|site5.com)|$) !poach_attempt
CustomLog logs/poachers_log combined env=poach_attempt 
<FilesMatch ".(jpg|jpeg|png|gif)">
Order Deny,Allow
Deny from env=poach_attempt
</FilesMatch>