First of all thank you very much Tsquez for your help!
When I turned on WP_DEBUG, WP_DEBUG_LOG and also WP_DEBUG_DISPLAY there is no any message on the screen. Also there is no file debug.log inside of wp-content folder. There is file debug.log of Woocommerce but is absolutely empty. So I will try to explain you with more details.
With you theme I like to develop one on line shop. Works like a charm an I like it so much. This is second time that I use Zurb Foundation and I have to tell you that I am very curious about this framework. First I did developed my own WP theme, based on ZF, but at the end I did decide to use yours because is obviously much better than mine.
Sometimes my clients, who are already familiar with WordPress, ask me for the on line shop. Woocommerce seems to be right choice for them.
There is only that “little obstacle”: when I click on the big image of product it does not open in lightbox.
Seems that my problem is hidden in the function my_post_image. When I change this part of code:
$html = '<a href="' . get_permalink( $post_id ) . '" title="' . esc_attr( get_the_title( $post_id ) ) . '">' . $html . '</a>';
return $html;
with:
$large_image_url = wp_get_attachment_image_src( get_post_thumbnail_id(), 'large');
$html = '<a href="' . $large_image_url[0] . '" rel="lightbox" title="' . esc_attr( get_the_title( $post_id ) ) . '">' . $html . '</a>';
return $html;
big image of product, on single product page, opens in light box. But unfortunately not only big pictures. When I click on the small thumbnails, instead of open new page, pictures open in lightbox because link is broken.
P.S.
Sorry for my English.