how to remove image-name shows on hover

or – you replace the text what is shown on hover – for example to show the alt attribut text.
If the image doesn’t have one – there will be nothing to see – if you have set an alt attribut this will show instead.

this to functions.php of your child theme

function image_alt_not_title(){
?>
<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', 'image_alt_not_title');