WodPress: How to show User gravatar from email

function wpmidia_gravatar() {
    global $current_user;
    get_currentuserinfo();
    $getuseremail = $current_user->user_email;
    $usergravatar = 'http://www.gravatar.com/avatar/' . md5($getuseremail) . '?s=32';
    echo '<img src="' . $usergravatar . '" class="gravatar" />';
}

Modo de usar:
<?php wpmidia_gravatar(); ?>