ciao,ma questo script che ho trovato fa l'upload dell'immagine con il nome originale della stessa,io invece voglio che la rinomini con un nome da me specificato;cosi ad ogni upload poichè l'immagine avrà sempre lo stesso nome sovrascriverà la precedente.Ecco lo script che sto usando io.....
function getExtension($str) {

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

define ("MAX_SIZE","400");

$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"))
{
echo ' Unknown Image extension ';
$errors=1;
}
else
{
$size=filesize($_FILES['file']['tmp_name']);

if ($size > MAX_SIZE*9000)
{
echo "You have exceeded the size limit";
$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);
}

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

$newwidth=80;
$newheight=($height/$width)*$newwidth;
$tmp=imagecreatetruecolor($newwidth,$newheight);



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



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


imagejpeg($tmp,$filename,100);


imagedestroy($src);
imagedestroy($tmp);

}
}
}
//If no errors registred, print the success message

if(isset($_POST['Submit']) && !$errors)
{
// mysql_query("update SQL statement ");
echo "Image Uploaded Successfully!";

}