Change uploading image name in php

if ($_FILES['img']['name'] != "") 
{
   $allowed_ext = array("jpg", "jpeg", "png", "gif");

   $extension = explode('.', $_FILES["img"]["name"]);  

   $ext = strtolower(end($extension));                                     
   if (in_array($ext, $allowed_ext)) 
   {
       $newname = rand(10000, 99999) . "_" . time() . "." . $ext;  

       $loc = "uploadedimages/" . $newname;
                                                move_uploaded_file($_FILES["img"]["tmp_name"], "./" . $loc);
   }
}