$cur_time = uniqid(funfile_world_);
$oname = $_FILES['image']['name'];
$oname = str_replace(" ","_",$oname);
$oname = str_replace("%20","",$oname);
$uploaddir  = 'files/';

       $new_filename = $cur_time . '_' . $oname;
       rename($uploaddir . $oname, $uploaddir . $new_filename);

there you go