Rinominare file in base all'id dell'utente loggato

[cape99]

ciao
ho creato un form per caricamento immagini e funziona benissimo, il problema arriva quando devo rinominare il file in base all'id dell'utente loggato che ho salvato nel database. Vi metto il php qui :
<?php
$target_dir = "uploads/";
$newFileName = $target_dir . 'nomefilenuovo' .'.'. pathinfo($_FILES["fileToUpload"]["name"] ,PATHINFO_EXTENSION); //get the file extension and append it to the new file name
$uploadOk = 1;
$imageFileType = pathinfo($_FILES["fileToUpload"]["name"] ,PATHINFO_EXTENSION);
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
$check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
if($check !== false) {
echo "File is an image - " . $check["mime"] . ".";
$uploadOk = 1;
} else {
echo "File is not an image.";
$uploadOk = 0;
}
}
// Check if file already exists
if (file_exists($target_file)) {
echo "Sorry, file already exists.";
$uploadOk = 0;
}
// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
echo "Sorry, your file is too large.";
$uploadOk = 0;
}
// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
$uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $newFileName)) {
echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";

} else {
echo "Sorry, there was an error uploading your file.";
}
}
?>