Click the Configure (cogwheel) icon to the right of your Product question, then click the "Products" tab.
Add your product names and details and click "Add Product +" on the left to add additional products.
Select a product from the left that you want to add images to.
Under the "Images" section of the product, click the "Add Images +" button to upload images for the product. You can upload multiple images to your products and re-order them. The first image will be used as the primary image for that product.
After you've uploaded your product images, you can use the built-in image editor to adjust levels, crop, resize, or even add annotations to them. Hover over the image in the Products tab, then click the pencil icon to open the image editor.