My product images look blurry, how can I fix this?

To fix the product images displayed, kindly try setting the image size of the product thumbnail the same as that of the box it is displayed in.
To change the product image dimensions, you will have to change Image Thumbnail settings in WooCommerce and regenerate the image thumbnails.

For the Custom Product Boxes plugin version 4.0.x and above:

Here is the article on how to fix it if you have coding knowledge.