PHP file uploader (i want it to over write)

[ali3011]

this is my code which working,and every image is posted with it's original name
but i want it to have little one..
i want it to overwrite the uploaded image

<?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.</div> ';
    $errors=1;
    }
    else
    {
    $size=filesize($_FILES['file']['tmp_name']);
    if ($size > MAX_SIZE*1024)
    {
    $change='<div class="msgdiv">Du har overskredet fil st&oslash;rrelsen!</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!</div>';
    }
    ?>

...um and one more thing..
can make it change the extension also ??

[ali3011]

i solved by myself.. thanks to any one who entered... ;)

i just removed
this
. $_FILES['file']['name']

from those two lines and defined a name inside the target

user_imgs/ali.png

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