resize gambar jadi 600x600

<?php
if($_FILES)
{
    //echo '<pre>';print_r($_FILES);
    /*
    Array
(
    [files] => Array
        (
            [name] => earth_and_moon-1280x800.jpg
            [type] => image/jpeg
            [tmp_name] => C:\xampp\tmp\php5E88.tmp
            [error] => 0
            [size] => 134688
        )

)
    */
    $filename0=$_FILES['files']['name'];
    copy($_FILES['files']['tmp_name'],'1.tmp');


// Content type
    $filename="1.tmp";
    $max=580;

// Get new dimensions
    list($width, $height) = getimagesize($filename);

    if($width>$height)
    {
        $persen=$width/$max;

    }else{
        $persen=$height/$max;
    }

    $width1=$width/$persen;
    $height1=$height/$persen;

    $x0=(600-$width1)/2;
    $y0=(600-$height1)/2;
    //die("$x0, $y0, 0, 0, $width1, $height1, $width, $height);");
    $new_width = 600;
    $new_height = 600;

    // Resample
    $image_p = imagecreatetruecolor($new_width, $new_height);
    $white = imagecolorallocate($image_p, 255, 255, 255);
    imagefill($image_p, 0, 0, $white);
    $image = imagecreatefromjpeg($filename);
    imagecopyresampled($image_p, $image,
    $x0, $y0, 0, 0,
    $width1, $height1, $width, $height);

// Output
    header('Content-Type: image/jpeg');
    header('Content-Disposition: attachment; filename="'.$filename0.'"');
    imagejpeg($image_p, null, 100);
    die();
}

?><!DOCTYPE html>
<html>
<head>
    <title></title>
<? /*    <script src="http://code.jquery.com/jquery-1.8.2.min.js"></script>

    <script src="../js/jquery-1.8.2.js"></script>
    <script src="../js/kendo.all.js"></script>
    <link href="styles/kendo.common.css" rel="stylesheet" />
    <link href="styles/kendo.default.css" rel="stylesheet" />
*/
?></head>
<body>
    <div class='myform' >
    <form enctype='multipart/form-data'  method="post" >
    Masukkan File
    <input name="files" id="myfiles" type="file" />
                    <p>
                        <input type="submit" value="Perbesar Gambar" class="k-button" />
    </form>
    </div>
    <!--
        <div id="example" class="k-content">


            <form method="post" action="" style="width:45%">
                <div>
                    <input name="files" id="files" type="file" />
                    <p>
                        <input type="submit" value="Submit" class="k-button" />
                    </p>
                </div>
            </form>
            <script>
                $(document).ready(function() {
                    $("#files").kendoUpload();
                });
            </script>
        </div>
-->

</body>
</html>