Sorry, disregard the previous message it was sent by mistake. Please try to deactivate the Masonry grid and Products grid with different sizes in the Theme Settings > Shop page > Product Style.
You have set min-width 600, however, all your initial image size is below 600. Try to upload a few images with equal size and check. As you see the tube is considerably cut and it is not good. This option works great when your image size differs not slightly to make the of one size.
Unfortunately, it is not possible to make a big image from a small one. Your images are considerably different. The only way is to upload images more or less in equal size.