Woocommerce Product Images stopped showing / changes to functions

Greetings,

Woocommerce product images have stopped showing in my store using the Powen Pro theme. The featured image shows, just not the additional images as thumbnails. I tracked down the issue to an update in woocommerce.
https://createandcode.com/broken-photo-gallery-and-lightbox-after-woocommerce-3-0-upgrade/

The fix recommended adding this code to the function file. I know how to add. However I’m not finding the file with after_theme_setup … Can you tell me which file I should add this to in the theme. (I’ll create a child theme).

add_action( ‘after_setup_theme’, ‘yourtheme_setup’ );

function yourtheme_setup() {
add_theme_support( ‘wc-product-gallery-zoom’ );
add_theme_support( ‘wc-product-gallery-lightbox’ );
add_theme_support( ‘wc-product-gallery-slider’ );
}

Thank you for your help!

The page I need help with: [log in to see the link]