Woocommerce thumbnail blurry

1. This is usually due to an incorrect setting in your WooCommerce settings. To fix this, go to WooCommerce > Settings > Products and make sure that the “Use product image thumbnails” setting is checked

2. Go to customizer > woocommerce > product image. make sure you select uncropped

Reference: https://woocommerce.com/document/fixing-blurry-product-images/