You need to add images to your products. Under each of the products visual editors look for the “Gallery Options” meta box. Click on the green “Add Image to slideshow” button to add at least one image to the products slideshow which the theme and woocommerce uses to then output that image for all of the plugins output.
The size of the image used is defined in the WooCommerce settings under the Catalog tab at the very bottom. It doesn’t change how the theme sizes the container of the image but the size of image that gets output by WooCommerce.
The individual options in the “Gallery Options” meta box determines how the image is displayed on the individual product page.