OT: How to attach an image as a link?

[joe at actionline.com]

How can I attach a business card image to an email message as a link
so that a recipient can click on the image to go to the corresponding
web page?

Click the link below to see a screen-shot example with an attached
image; but in this example, the image is (not clickable):

- - - http://www.upquick.com/temp/cardlink.jpg - - -

What html code would be needed to make the attachment clickable?