To add a Size Guide button that opens an image in lightbox based on category (ring or bangle) and if variation size is set -- WooCommerce

size.php

<?php

//To add a Size Guide button that opens an image in lightbox based on category (ring or bangle) and if variation size is set -- WooCommerce
//Use lightbox of your choice

add_action( 'woocommerce_before_add_to_cart_button', 'vg_sizing_placement', 5 ); 

function vg_sizing_placement() {

    global $product, $post;

    if( is_single() && $product->is_type( 'variable' ) ) {

        $attributes = $product->get_attributes();

        foreach ( $attributes as $attribute ) {
            if ( $attribute['name'] == 'pa_' . 'size' ) {
                
                $product_cats = wp_get_post_terms( get_the_ID(), 'product_cat' );

                foreach ($product_cats as $key => $value) {
                    $parents[] = $value->parent;
                }

                if( in_array( 'rings', $parents ) ) {
                    
                    ?>
                    <div id="sizeimg">
                        <a href="#" data-featherlight="<URL OF RING SIZE IMAGE>">Size Guide</a>
                    </div>
                    <?php
                
                } else if( in_array( 'bangles', $parents ) ) {
                    
                    ?>
                    <div id="sizeimg">
                        <a href="#" data-featherlight="<URL OF BANGLE SIZE IMAGE>">Size Guide</a>
                    </div>
                    <?php
                
                }
            
            }
        }    

    }

}