Displaying incorrect Gravatar

Question

I posted on this site earlier on questioning how to implement Gravatars into my php blog. I got an excellent answer but I've had one issue. The code displays the incorrect avatar. Any help is appreciated.

Code:

    <?php

    function get_gravatar( $email, $s = 40, $d = 'identicon', $r = 'g', $img = false, $atts = array() ) {
        $url = 'http://www.gravatar.com/avatar/';
        $url .= md5( strtolower( trim( $email ) ) );
        $url .= "?s=$s&d=$d&r=$r";
        if ( $img ) {
            $url = '<img src="' . $url . '"';
            foreach ( $atts as $key => $val )
                $url .= ' ' . $key . '="' . $val . '"';
            $url .= ' />';
        }
        return $url;
    }

}
$commenttimestamp = strtotime("now");

$sql = "SELECT * FROM php_blog_comments WHERE entry='$id' ORDER BY timestamp";
$result = mysql_query ($sql) or print ("Can't select comments from table php_blog_comments.<br />" . $sql . "<br />" . mysql_error());
while($row = mysql_fetch_array($result)) {
    $timestamp = date("l F d Y", $row['timestamp']);
    printf("<hr />");
    print("<p>" . stripslashes($row['comment']) . "</p>");
    printf("<p>Comment by <a href=\"%s\">%s</a> @ %s</p>", stripslashes($row['url']), stripslashes($row['name']), $timestamp);
    echo $imagetag = "<img src='" . get_gravatar($email) . "' />";
    printf("<hr />");
}
?>