Gravatars : Add, Reorder and change Default

<?php
/**
    Inspired by this thread:
                  www.wptavern.com/forum/themes-templates/1756-default-avatar-filter-hooks.html
    Author: brasofilo
    Description: adds two gravatars to the list, marks the first one as default, deletes all WP built-in gravatars
    Usage: drop in your functions.php - change $del_defaults to suit your needs
*/

if ( !function_exists('bsf_addgravatar') ) {
    function bsf_addgravatar( $avatar_defaults ) {
        $temp_avatars = $avatar_defaults;
        unset($avatar_defaults);

        // files are inside your-theme/images directory
        $pathavatar = get_bloginfo('template_directory');
        $myavatar1 = $pathavatar . '/images/avatar1.gif';
        $myavatar2 = $pathavatar . '/images/avatar2.png';
        $bavatar[$myavatar1] = 'New Avatar';
        $bavatar[$myavatar2] = 'Brand New Bravatar';

        $del_defaults = true; // Your option...

        if($del_defaults) $avatar_defaults = $bavatar;
        else $avatar_defaults = array_merge((array)$bavatar, (array)$temp_avatars);

        // best way i found to get rid of the 'mystery' default
        $default = get_option('avatar_default');
        if ( empty($default) || $default=='mystery' ) update_option( 'avatar_default', $myavatar1);

        return $avatar_defaults;
    }
    add_filter( 'avatar_defaults', 'bsf_addgravatar' );
}