Update UploadHandler.php

parameter to manage random file name:
'random_file_name' => &lt;false|true&gt; 
'random_file_name_prefix' => time() . "-"
'random_file_name_lenght' => 10
if option "random_file_name" is set to true, will be generated a new filename as &lt;timestamp&gt;-&lt;10_chars_alphanumeric_random&gt;.&lt;ext&gt;