// users.php
  $status = move_uploaded_file(
    $_FILES["profile_picture"]["tmp_name"],
    'user_images/' . $targetFile
  );

  if ($status) {
    try {
      $con->beginTransaction();

      $query = "INSERT INTO `users`(`display_name`,
`user_name`, `password`, `profile_picture`)
VALUES('$displayName', '$userName', '$encryptedPassword', '$targetFile');";

      $stmtUser = $con->prepare($query);
      $stmtUser->execute();

      $con->commit();

      $message = 'user registered successfully';
    } catch (PDOException $ex) {
      $con->rollback();
      echo $ex->getTraceAsString();
      echo $ex->getMessage();
      exit;
    }
  } else {
    $message = 'a problem occured in image uploading.';
  }

  header("location:congratulation.php?goto_page=users.php&message=$message");
  exit;
}