For a public wiki the avatar image is successfully loaded, for ex. http://wiki.mywiki.org/images/avatars/972/128.png
It seems the Extension:Avatar is not compatible with Image authorization (https://www.mediawiki.org/wiki/Manual:Image_authorization):
$wgUploadPath = "$wgScriptPath/img_auth.php"; $wgUploadDirectory = '</absolute/path/to/my/doc_root>/../<dir_name_unguessable>'; $wgEnableUploads = true;
Therefore the avatar image fails with 403 Forbidden, for ex. http://wiki.mywiki.org/img_auth.php/avatars/2/128.png:1