Was just trying out your avatar plugin with WordPress multisite.
In the main options-discussion.php settings page the default avatars appear as broken images.
I fixed this by doing this in the plugin - don't know if this is the best fix or if there is something else that is causing the issue.
// No local avatar source, so build global avatar source...
if(!$src || basename( $_SERVER['REQUEST_URI'] ) == 'options-discussion.php' ) {
