disabling the lightbox on WooCommerce Single product image. use this code in your child theme functions.php

functions.php

function custom_single_product_image_html( $html, $post_id ) {
    $post_thumbnail_id = get_post_thumbnail_id( $post_id );
    return get_the_post_thumbnail( $post_thumbnail_id, apply_filters( 'single_product_large_thumbnail_size', 'shop_single' ) );
}
add_filter('woocommerce_single_product_image_thumbnail_html', 'custom_single_product_image_html', 10, 2);