I tried the lazyload feature on this site and it seemed to work mostly fine except I noticed there were duplicate thumbnails on the woocommerce cart page. I went into the settings and added "/cart" and "/cart/" and even the CSS class of the cart table to the exclusions, but it kept displaying the duplicate thumbnails. Only thing that removed the duplicate thumbnails was deactivating the entire lazyload feature. So may be a bug there.
Also the CSS class exclusion doesn't accept selectors with spaces. For example if your selector is something like:
.woocommerce table.cart img.thumbnail
It will break that up at the spaces, so you'll end up with: