1) It can be related to your image dimensions in WC plugin settings. Could you, please, provide me temporary admin panel access.
2) Provide me FTP access, please, we’ll fix it.
3) I don’t see any subitem in your menu. Provide me temporary admin panel access to create subitems and check.
1) I have enabled the default WooCommerce theme – Storefront – and see the same problem with featured image http://prntscr.com/iash28 Looks like it’s some problem with your images or with the way how you uploaded them to your Dashboard http://prntscr.com/iasm8i . WordPress and Woocommerce plugin use different image sizes for catalog image, single product, thumbnails (WooCommerce > Setting > Products > Display) and WP generates images with these sizes and uses them when it’s needed. But your images do not have such sizes and even Regenerate thumbnails plugin does not work for you. Contact WP or WC support to solve this problem. Unfortunately, theme support can help you only with problems related strictly to our theme. WordPress or WooCommerce default problems are outside the scope of our support