Click the "Graphic/Applet" button, under the "Graphic Element Type "select "Local Image + link to URL"
Select the image you would like to use as a link
Type in the URL for the link in the "URL for Link" field. Click "Done", then regenerate the course.
To control the display size of any graphic, fill in the Height and/or Width fields. If you leave either of them as "-1", the browser will scale the image based on the other.