Ticket #25764: restore-auto-generated-gravatars.php

<?php
/*
Plugin Name: Restore Auto-Generated Gravatars
Version: 0.1
Plugin URI: http://core.trac.wordpress.org/ticket/25764
Description: Restores auto-generated Gravatar images on Dashboard and Edit Comments screens.
Author: Sergey Biryukov
Author URI: http://profiles.wordpress.org/sergeybiryukov/
*/

function restore_auto_generated_gravatars_25764( $avatar, $id_or_email, $size, $default, $alt ) {
        if ( ! is_admin() )
                return $avatar;

        $screen = get_current_screen();
        if ( ! in_array( $screen->id, array( 'dashboard', 'edit-comments' ) ) )
                return $avatar;

        remove_filter( 'get_avatar', 'restore_auto_generated_gravatars_25764' );

        $default = get_option( 'avatar_default' );
        $avatar = get_avatar( $id_or_email, $size, $default, $alt );

        add_filter( 'get_avatar', 'restore_auto_generated_gravatars_25764', 10, 5 );

        return $avatar;
}
add_filter( 'get_avatar', 'restore_auto_generated_gravatars_25764', 10, 5 );