//Gets gravatar image from email address
function get_gravatar( $email, $s = 150, $d = 'mm', $r = 'g', $img = false, $atts = array() ) {
    $url = 'https://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;
}

function if_gravatar($email){
	$email2 = md5(strtolower($email));
	$gravatar = "http://www.gravatar.com/avatar/$email2?d=404";
	$headers = get_headers($gravatar,1);
	if (strpos($headers[0],'200')) $gravatar = true; // OK
	else if (strpos($headers[0],'404')) $gravatar = false; // Not Found
}