After I added Hotlink Protection .htaccess code, my website images are not being shown at facebook pages when some user pastes a link to my site.
I added facebook to the whitelist like this.
SetEnvIfNoCase Referer "^(http|https)://www\.mysite\.com.*$" whitelist SetEnvIfNoCase Referer "^(http|https)://.*google.*" whitelist SetEnvIfNoCase Referer "^(http|https)://.*yahoo.*" whitelist SetEnvIfNoCase Referer "^(http|https)://.*bing.*" whitelist SetEnvIfNoCase Referer "^(http|https)://.*anothersite.wordpress.*" whitelist SetEnvIfNoCase Referer "^(http|https)://.*facebook.*" whitelist
The images are not being shown at facebook and I receive this kind of security log entries:
[403 GET / HEAD Request: August 22, 2014 4:27 pm] Event Code: BFHS - Blocked/Forbidden Hacker or Spammer Solution: N/A - Hacker/Spammer Blocked/Forbidden REMOTE_ADDR: 173.252.120.118 Host Name: 173.252.120.118 SERVER_PROTOCOL: HTTP/1.1 HTTP_CLIENT_IP: HTTP_FORWARDED: HTTP_X_FORWARDED_FOR: HTTP_X_CLUSTER_CLIENT_IP: REQUEST_METHOD: GET HTTP_REFERER: REQUEST_URI: /wp-content/uploads/2012/10/photo-2645.jpg QUERY_STRING: HTTP_USER_AGENT: facebookexternalhit/1.0 (+http://www.facebook.com/externalhit_uatext.php)