The function of img_auth.php is to output files from a private wiki. This wiki is configured as a public wiki. For optimal security, img_auth.php is disabled.
MediaWiki:Img-auth-public
From Dr. Joey Paquet Web Site
The function of img_auth.php is to output files from a private wiki. This wiki is configured as a public wiki. For optimal security, img_auth.php is disabled.
