Rename file during upload

[gm8net]

Could someone please help me with the code below, I want the file that is being uploaded to be renamed with a random number in addition to the unix timestamp to prevent a filename from ever being duplicated.

I also want to check that files being uploaded are .jpg, .jpeg, .gif, or .png

I've been trying for ages done a lot of googling but can't seem to get it to work for me.

echo 'Upload result:<br>'; 
$uploaddir = dirname($_SERVER['SCRIPT_FILENAME'])."/UploadedFiles/";

$target_encoding = "ISO-8859-1";
echo '<pre>';
if(count($_FILES) > 0)
{
	$arrfile = pos($_FILES);
	$uploadfile = $uploaddir . iconv("UTF-8", $target_encoding,basename($arrfile['name']));

	if (move_uploaded_file($arrfile['tmp_name'], $uploadfile))
	   echo "File is valid, and was successfully uploaded.\n";
}
else
	echo 'No files sent. Script is OK!'; 
echo 'Here is some more debugging info:';
print_r($_FILES);

echo "</pre>";

?>

[Clark Wells]

Gm -

Try this for the Required Filetypes:

$allowed_filetypes = array('.jpg','.gif','.jpeg','.png');  

// Get the name of the file (including file extension).
$filename = $_FILES['userfile']['name'];

// Get the extension from the filename.
 $ext = substr($filename, strpos($filename,'.'), strlen($filename)-1);

 // Check if the filetype is allowed, if not DIE and inform the user.
   if(!in_array($ext,$allowed_filetypes))
      die('The file you attempted to upload is not allowed.');