Does it seem like lightbox is broken after upgrading to Woocommerce 3.0. This is because the latest versions of Woocommerce does not automatically encode Lightbox support functions. It is recommended to use a theme that declares Woocommerce support to get the Lightbox functions. If you are using a theme that is not Woocomerce compatible you can still implement these features. Do this by having your web developer add the Woocommerce support functions to your themes functions file. If you are managing your own file system then you can add the needed actions yourself.

How To Fix Lightbox

Previous versions of Woocommerce had an option to enable the Light box gallery in the Woocommerce settings. It is found under Woocommerce --> Settings --> Products --> Display. If you go to this section and do not see this option it could be that you are using a theme that does not declare Woocommerce support. If this is the case you can open your functions.php file in your active theme and edit the following lines ("your_theme_setup" will actually be the name of your theme processor):

add_action( 'after_setup_theme', 'your_theme_setup' );

function your_theme_setup() {
add_theme_support( 'wc-product-gallery-zoom' );
add_theme_support( 'wc-product-gallery-lightbox' );
add_theme_support( 'wc-product-gallery-slider' );
}