Wordpress gravitar addons

add_filter( 'avatar_defaults', 'newgravatar' );  
  
function newgravatar ($avatar_defaults) {  
    $myavatar = get_bloginfo('template_directory') . '/images/buildinternet-gravatar.jpg';  
    $avatar_defaults[$myavatar] = "Build Internet";  
    return $avatar_defaults;  
}