Disable the Default Lightbox in WooCommerce 3.0+

Here is a quick way to disable the Lightbox in WooCommerce 3.0 and above. Add the following code to your functions.php file:

add_action( 'after_setup_theme', 'remove_wc_gallery_lightbox', 100 );

function remove_wc_gallery_lightbox() { 
  remove_theme_support( 'wc-product-gallery-lightbox' );
}

For more WooCommerce customization, see Mastering WooCommerce Hooks.