How to generate barcode as image and save on my server?

I'm creating a landing page where the user signs up and will be generated a bar code that is sent via email to the user on a discount coupon, barcode.inc.php to generate the barcode image, I need to save that image on my server to use when sending the email, how could I do that?

Here's my code:

require_once('barcode.inc.php'); 
$code_number = '125689365472365458';//125689365472365458 
new barCodeGenrator($code_number,0,'hello.gif', 190, 130, true);