Code-Snippets-Functions/Execute a function on a child site/WooCommerce/image-to-external-url-single-product.txt

add_filter( 'woocommerce_single_product_image_thumbnail_html', 'wc_image_link_external_url', 100, 2 );
 
function wc_image_link_external_url( $html, $post_thumbnail_id ) {
   global $product;
   if ( ! $product->is_type( 'external' ) ) return $html;
   $url = $product->add_to_cart_url();
   $pattern = "/(?<=href=(\"|'))[^\"']+(?=(\"|'))/";
   $html = preg_replace( $pattern, $url, $html );  
   return $html;
}