my name is travis, i am a support agent for webune.com and i get this question quite frequently.
all you have to do if you want to add a link with a picture is use the img and href tags in html.
here is an example code you can use:
lets say i have this picture:
and i want to link this picture to htt://www.webune.com i would use this code to do that:
<a href="http://www.webune.com"><img src="http://webune.com/images/logo4.jpg" alt="webune" width="280" height="50" border="0"></a>
and this is how it would like like, try it, click on the image below: