The gallery isn't visible

Hello.
You have a problem in your theme or installed plugins, it include jquery library 2 times, you can look into your web page source code, first one – around 165 line:
<script type=’text/javascript’ src=’https://novaya-gatchina.ru/wp-includes/js/jquery/jquery.js?ver=1.11.3′></script&gt;
and this is correct adding jquery to WordPress theme, and second one around line 254:
<script type=”text/javascript” src=”https://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js”></script&gt;
and this is not correct, as this library should be included from your WordPress site, and also – there are no need to include one and same library 2 times – that’s why you have javascript errors and conflicts on your site. Ask you theme developer to fix this (use only first jquery connection) – and I think all functionality on your site should start working fine, including our plugin.

Unfortunately, this topic was last updated May 1, 2014, and it looks like the author is no longer involved ?? Maybe if you prompt as, I can fix this problem yourself?

Hello.
Sure, we will try, but I need at least see your site, now it is on Maintenance mode. Can you enable it?

Of course, it turned out:)

Hello! Are there any changes concerning my problem?

Hello.
I just checked your site https://novaya-gatchina.ru/%D0%B7%D0%B0%D0%BF%D0%B0%D0%B4%D0%BD%D0%B0%D1%8F-%D0%B4-16/ . You have javascript error there, please check this screenshot https://screencast.com/t/p8zJQmMos5h . Can you ask your web developer to fix them? As those errors can just simply stop all other javascript execution. Also, ask youe developer to not include old jquery library from outside WordPress:
<script type=”text/javascript” src=”https://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js”></script&gt;
It is already included in your site in line before:
<script type=’text/javascript’ src=’https://novaya-gatchina.ru/wp-includes/js/jquery/jquery.js?ver=1.11.3′></script&gt;