image name in lightbox on productdetail page

try to add on your child-theme functions.php:

function gallery_title_fix(){
?>
<script>
(function($){
    $(window).load(function() {
      $('.lightbox-added img').each(function(){
            var lin = $(this).attr('alt');
            $(this).attr('title',lin);
        });
    });
})(jQuery);
</script>
<?php
}
add_action('wp_footer', 'gallery_title_fix');

this will show instead of the title the description of the media set on Media – i guess you will find similar things for alt Attribut