Modify to randomize Default Avatar?

Greetings! I have been trying for days to find a solution to this problem. I’ve used a bunch of code that does what your plugin does, such as this:

if ( !function_exists('fb_addgravatar') ) {
function fb_addgravatar( $avatar_defaults ) {
$myavatar = get_bloginfo('template_directory') . '/images/avatars/avatar_' . (string) rand(1,5) . '.png';
$avatar_defaults[$myavatar] = 'Users';
return $avatar_defaults; }
add_filter( 'avatar_defaults', 'fb_addgravatar' ); }

But your plugin is a nice option and works well with the Local Avatar plugin. I’m wondering if there is a way to modify the plugin to pick from a folder of avatars and assign a random avatar (say out of a folder of 10) to all commenters without an Avatar.

Any help or ideas would be GREATLY appreciated!

Thank you and great plugin!
Brandon

http://ww.wp.xz.cn/extend/plugins/add-new-default-avatar/