uploadify image random name generating

gistfile1.php

<?php
if (!empty($_FILES)) {
	$tempFile = $_FILES['Filedata']['tmp_name'];
	$targetPath = $_SERVER['DOCUMENT_ROOT'] . $_GET['folder'] . '/images/products/';
	$ext = pathinfo($_FILES['Filedata']['name'], PATHINFO_EXTENSION);
	$newFileName = md5($tempFile.microtime()).'.'.$ext;
	$targetFile =  str_replace('//','/',$targetPath) . $newFileName;
	move_uploaded_file($tempFile,$targetFile);
}
echo $newFileName;
?>