Sintak upload gambar di PHP

Berikut ini adalah sintak untuk upload gambar dalam pemrograman php :

<?php
$id_pengawas=$_SESSION['id_pengawas'];
 $url = isset($_SERVER['HTTP_REFERER']) ? htmlspecialchars($_SERVER['HTTP_REFERER']) : '';
$target_dir = "img_pengawas/";       // folder untuk menyimpan gambar yang terupload
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = pathinfo($target_file,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" && $imageFileType != "JPG" && $imageFileType != "PNG"
&& $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"], $target_file)) {
       $h=mysql_query("update t_pengawas set  foto='$target_file' where id_pengawas='$id_pengawas'");
  if($h){
   header("location:home.php?page=profil");
        }

    } else {
        echo " <a href='$url' class='btn btn-primary'>Go Back</a><br>
        Sorry, there was an error uploading your file.";
    }
}
?>