Just to clarify, you are using Surveyor, correct? Not Sculptor?
You posted in the Sculptor forum, but you're talking about Surveyor.
It appears you have created an HTML Site map. On the HTML Site map page, you can add images to it the same way you would add images to any other page in Dreamweaver. You would use the img tag to add images.
To get to the Design tab in Dreamweaver, you would look in the top left corner of the coding window and see the 3 buttons that say Code, Split and Design. Click on the Design or Split buttons. The split button shows part code and part design view.