How do I insert email address from form submission into img src tag?

How do I insert email address from form submission into img src tag?

Hi guys need a little assist. I have a newsletter sign up form that I want to add a subscriber to a Bronto newsletter listing. Bronto gives me an <img> tag the source looks a little something like so: 

  1. <img src="http://app.bronto.com/public/?q=direct_add&fn=Public_DirectAddForm&id=azwpqvjgpymtfjtylrmjyverwlopbli&email=example@example.com&doubleOptin=1&sendWelcome=yes&messageId=3f40ed9b14c78514cbc027a43381e1ee&fromName=SAmple+Online&fromAddress=info@example.com" width="0" height="0" border="0" alt=""/>
The idea here is to replace the email value with my subscribers value after the form is submitted.

Any ideas on how I could possibly accomplish this. Any help would be greatly appreciated.

Stata buon.