Hi @kaixer,
For the image quality, this is what you want to do:
Ok here is what you want to do:
1) Copy /woocommerce/single-product/product-image.php to your child theme (inc structure).
2) Edit line 92, replacing 562 with the width of image you want:
$image = aq_resize( $image_link, 562, NULL, true, false);
– Ed