Your main shop page is set to show each style. Then when clicked will show all available options for that style. In order for the style to have a photo on that main shop page, you have to go into your “Categories” and set a featured image.
In your dashboard, on the left find and hover over “Products” and select “Categories”
Hover over the style you need to add a photo to and click “edit”
Click “upload/add image”
From this screen locate the image you would like to add. If it is not already loaded to your media library, then click the “Upload Files” tab and follow through those instructions. Once you have selected the image, it is very important that you give it a “Title” and “Alt Title”. This is one of the ways that google and other search engines bring people to your site. After you set the “title” and “alt title”, click “Use Image”
Your image you choose will now show up as the styles featured image. Click save at the bottom of the page and you are done.