Hi Simon,
In order for any graphics to appear you would need to send an HTML message. The image to display would need to be uploaded to your site via FTP and accessible via a URL, referenced to in the message.
For example:
<html>
<body>
<img src="http://example.com/email-images/top-logo.gif"><br>
<br>
Welcome to our newsletter!<br>
<br>
More stuff here....
</body>
</html>
I recommend a Google for
html tutorial to learn more about formatting fonts, setting up tables (for multiple columns), links, etc.
To avoid having to create a text version of your messages, which is required for those email clients that do not support HTML or have it disabled, I recommend simply using a message code of the type "Link to HTML" as the text message.
Please let me know if I can be of further assistance
Regards