How to code an image button to call mail.php on contact form Options

[larry78723]

My contact form starts with:

<form id="form1" method="POST" action="mail.php">

I'd like to replace the last line in my contact from:

<button type="submit" value="Send" style="margin-top:15px; margin-left: 500px; text-align: center;">Send Email</button>

with one that contains

<img src="images/button_send-email.png" alt="Email">

but have no idea what it should look like. I tried <a href "mail.php" <img src="images/button_send-email.png" alt="Email"> > but the button doesn't even show.

Please teach me how this should be done.

Thanks in advance,
Larry