Our theme follows standards of woocommerce and we use recommended functions of woocommerce. But sometimes it’s not enough, so, we extend them.
By default, woocommerce set own image sizes for all images in shop. Basically, it has 3 size: Single image on product page (not cropped, full width), image in product loops (cropped, 270 px width) and small gallery images (100px width).
The most common problem is images in product loops (thumbnail images), because each site can have absolutely different image ratio, preferable sizes of images and quality. So, if everything is ok on your site – leave it as is. But, you can change next things:
Crop. You can disable it. For this, go to Customize – Woocommerce – Product images and disable crop or set another ratio for crop
Size. If changing crop is not enough for you, it’s possible to set own size for images in product grid. For this, go to theme option – loop customization and set own size.