update funktion virker ikke

scriptet henter fint den ønsket post men kan ikke update "image_ok" til 1
hvad pokker har jeg gjort galt

<?php
include ("htmltop.php");

?>

<!-- Venstre menu start -->
<?php
include ("menu.php");
?>
<!-- Venstre menu slut -->

<!-- Midter menu start -->

<td valign="top">
<?

//if($session->logged_in){
if($session->isAdmin()){ 
?>

    <?
        $image_username2=$_GET[user]; 
$result = mysql_query("SELECT * FROM image WHERE image_username = '$image_username2'");
if (!$result) print mysql_error();
while ($row = mysql_fetch_assoc($result)) {
$image_name = $row['image_name'];
print $row['image_username']. '&nbsp;'.$row['email']."<br>";

    echo "<br> <center><img src='userpics/$image_name'></center>";

}
       


if(isset($_POST['ret'])) {
  mysql_query("UPDATE image SET image_ok=1 WHERE image_username ='$image_username'");
}
?>

<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">

<input type="submit" name="ret" value="Godkend">



</td>

<!-- Midter menu slut -->

<!-- Højre menu start -->
<td width="100">menu h&oslash;jre</td>
<!-- Højre menu slut -->

















<!-- <br>
<a href="upload.php" title="Upload billed">upload.php</a> -->
<?
}
else{
  echo "You are not allowed to view this page";
}
?>
<?php
include "htmlbund.php";
?>