Enable WooCommerce Support for Lightbox, Zoom and Slider

When you use WooCommerce 3 or newer, you have to enable support for zoom, lightbox and/or slider at theme level. To do that, add the desired lines to your functions.php:

add_action( 'after_setup_theme', 'woocommerce_galery_features' );

function woocommerce_galery_features() {
    add_theme_support( 'wc-product-gallery-zoom' ); // enable image zoom
    add_theme_support( 'wc-product-gallery-lightbox' ); // enable image lightbox
    add_theme_support( 'wc-product-gallery-slider' ); // enable sliding image transition
}