Php upload script med navneskift

<?php
error_reporting(0);

$change="";
$abc="";


define ("MAX_SIZE","400");
function getExtension($str) {
        $i = strrpos($str,".");
        if (!$i) { return ""; }
        $l = strlen($str) - $i;
        $ext = substr($str,$i+1,$l);
        return $ext;
}

$errors=0;
 
if($_SERVER["REQUEST_METHOD"] == "POST")
{
    $image =$_FILES["file"]["name"];
    $uploadedfile = $_FILES['file']['tmp_name'];
   

    if ($image)
    {
   
        $filename = stripslashes($_FILES['file']['name']);
   
          $extension = getExtension($filename);
        $extension = strtolower($extension);
       
       
if (($extension != "jpg") && ($extension != "jpeg") && ($extension != "png") && ($extension != "gif"))
        {
       
            $change='<div class="msgdiv">Ukendt fil format.<br /><br /></div> ';
            $errors=1;
        }
        else
        {

$size=filesize($_FILES['file']['tmp_name']);


if ($size > MAX_SIZE*1024)
{
    $change='<div class="msgdiv">Du har overskredet fil størrelsen!<br /><br /></div> ';
    $errors=1;
}


if($extension=="jpg" || $extension=="jpeg" )
{
$uploadedfile = $_FILES['file']['tmp_name'];
$src = imagecreatefromjpeg($uploadedfile);

}
else if($extension=="png")
{
$uploadedfile = $_FILES['file']['tmp_name'];
$src = imagecreatefrompng($uploadedfile);

}
else
{
$src = imagecreatefromgif($uploadedfile);
}

echo $scr;

list($width,$height)=getimagesize($uploadedfile);


$newwidth=400;
$newheight=($height/$width)*$newwidth;
$tmp=imagecreatetruecolor($newwidth,$newheight);


$newwidth1=193;
$newheight1=143;
$tmp1=imagecreatetruecolor($newwidth1,$newheight1);

imagecopyresampled($tmp,$src,0,0,0,0,$newwidth,$newheight,$width,$height);

imagecopyresampled($tmp1,$src,0,0,0,0,$newwidth1,$newheight1,$width,$height);


$filename = "user_imgs/". $_FILES['file']['name'];

$filename1 = "user_imgs/thumbs/small". $_FILES['file']['name'];



imagejpeg($tmp,$filename,100);

imagejpeg($tmp1,$filename1,100);

imagedestroy($src);
imagedestroy($tmp);
imagedestroy($tmp1);
}}

}

//If no errors registred, print the success message
if(isset($_POST['Submit']) && !$errors)
{

  // mysql_query("update {$prefix}users set img='$big',img_small='$small' where user_id='$user'");
    $change=' <div class="msgdiv">Billedet blev uploadet succesfuldt!<br /><br /></div>';
}

?>