ด่วนครับ เรื่องการเปลี่ยนเส้นทางของPHP

<?error_reporting(1);?>
<?
$data = file_get_contents("num.txt");
$i=$data+1;
if($i>3)
{
	$ia=1;
	$strFileNamea = "num.txt";
	$objFopena = fopen($strFileNamea, 'w');
	fwrite($objFopena, $ia);
	fclose($objFopena);
}
else
{
	$strFileName = "num.txt";
	$objFopen = fopen($strFileName, 'w');
	fwrite($objFopen, $i);
	fclose($objFopen);
}
$datax=($_GET['a']);

function loadjpeg($imgname)
{
    /* Attempt to open */
    $im = @imagecreatefromjpeg($imgname);

    /* See if it failed */
    if(!$im)
    {
        /* Create a black image */
        $im  = imagecreatetruecolor(150, 30);
        $bgc = imagecolorallocate($im, 255, 255, 255);
        $tc  = imagecolorallocate($im, 0, 0, 0);

        imagefilledrectangle($im, 0, 0, 150, 30, $bgc);

        /* Output an error message */
        imagestring($im, 1, 5, 5, 'Error loading ' . $imgname, $tc);
    }
    return $im;
}
header('Content-Type: image/jpeg');
switch ($data){
		case 1:
			$img = loadjpeg('http://img.ihere.org/uploads/7ab5ae2cbf.jpg');
		break;
		case 2: 
			$img = loadjpeg('http://img.ihere.org/uploads/c6d38012f2.jpg');
		break;
		case 3: 	
			$img = loadjpeg('http://img.ihere.org/uploads/bc70959445.jpg');
		break;
		default:
			$img = loadjpeg('http://img.ihere.org/uploads/3b46ccd51d.jpg');
		break;
		}
imagejpeg($img);
imagedestroy($img);
?>