switch ($_GET['id'])
{
case '1a':
$name = "foto/1.jpg";
$fp = fopen($name, 'rb');
header("Content-Type: image/jpeg");
header("Content-Length: " . filesize($name));
fpassthru($fp);
break;
case '2a':
$name = "foto/2.jpg";
$fp = fopen($name, 'rb');
header("Content-Type: image/jpeg");
header("Content-Length: " . filesize($name));
fpassthru($fp);
break;
......