Image linking and lightbox

So, the problem is that on Expositio theme they are adding some jQuery code to all links, that if you're not closing the mobile menu, after a configurable number of seconds (1 second by default) just redirect site to the link url.

If you go to line 260 of js/functions.js you find this:

$('a').on('click', function(e) {
    e.preventDefault();
    var _this = $(this);
    // close mobile menu if it's open, redirect otherwise
    if (_body.hasClass('toggled-on') && _this.parents('#page').length == 1
        && _this.parents('#primary-navigation').length == 0
    ) {
        load_effect.menuOff();
    } else {
        load_effect.loader.show();
        var href = $(this).attr('href');
        $('.site').css('opacity', 0);
        setTimeout(function() {
            window.location = href;
        }, load_effect.duration);
    }
});

I think the best solution would be to create a child theme, dequeue that script and enqueue a copy of the script without that redirect:

<?php
// hook in late to make sure the parent theme's registration 
// has fired so you can undo it. Otherwise the parent will simply
// enqueue its script anyway.
add_action('wp_enqueue_scripts', 'override_functions_script', 100);
function override_functions_script()
{
    wp_dequeue_script('expositio-script');
    wp_enqueue_script('child-expositio-script', get_stylesheet_directory_uri().'/js/functions.js', array('jquery'));
}

And on your child functions.js, you could only redirect page if the link doesn't have fancybox class:

$('a').on('click', function(e) {
    e.preventDefault();
    var _this = $(this);
    // close mobile menu if it's open, redirect otherwise
    if (_body.hasClass('toggled-on') && _this.parents('#page').length == 1
        && _this.parents('#primary-navigation').length == 0
    ) {
        load_effect.menuOff();
    } else {
        load_effect.loader.show();
        var href = $(this).attr('href');
        $('.site').css('opacity', 0);
        if(!_this.hasClass('fancybox')) {  // only redirect if it doesn't have fancybox class
            setTimeout(function() {
                window.location = href;
            }, load_effect.duration);
        }
    }
});

Also, it would be good to report that to theme developer as they shouldn't have that code on a so generic rule.