Imaging - I'm obviously missing something

You set an item layout of type "list" which doesn't allow the display of images.
First, go in the menu Display->Content menus and edit the menu with the id 58. In the options, set the layout type to div and save.

Also, you're saying that you added the image in the description of the product. Unless you use the item layout to "image and description" in these options, the description won't be displayed on the listing of products. So, either you use the item layout "image and description", or you add your images in the "images" area of each product and not in the description.