更改登录用户php的profle-pic

我正在创建一个带有用户注册和登录系统的网站。用户可以通过注册在数据库中为提供几个选项。但现在我添加了一个选项来上传你的个人资料图片。但我只能更改脚本中提到的那个，而不能更改登录的用户。有人能帮我吗？

<?PHP
require_once("./include/fg_membersite.php");
require_once("./include/membersite_config.php");
if(!$fgmembersite->CheckLogin())
{
    $fgmembersite->RedirectToURL("login.php");
    exit;
}
?>
<?php session_start();
    $_SESSION['username'] = "ademd";
?>
 
<?php
if(isset($_POST['submit'])){
    move_uploaded_file($_FILES['file']['tmp_name'],"images/".$_FILES['file']['name']);
    $con = mysqli_connect("voetbaltransfermarkt.nl.mysql","voetbaltransfer","","voetbaltransfer");
    $q = mysqli_query($con, "UPDATE fgusers3 SET image = '".$_FILES['file']['name']."' WHERE username = '".$_SESSION['username']."'");
}
?>