https://bowmanflyfishing.com/lightbox.js?v=2

1// Bowman Fly Fishing — Lightbox Gallery
2(function() {
3  var lb = document.getElementById('lightbox');
4  if (!lb) return;
5  var img = lb.querySelector('.lightbox-img');
6  var counter = lb.querySelector('.lightbox-counter');
7  var images = [];
8  var idx = 0;
9
10  function attach(selector, getSrc) {
11    var nodes = document.querySelectorAll(selector);
12    if (!nodes.length) return;
13    var groupImages = [];
14    nodes.forEach(function(node) { groupImages.push(getSrc(node)); });
15    nodes.forEach(function(node, i) {
16      node.style.cursor = 'pointer';
17      node.addEventListener('click', function() {
18        images = groupImages;
19        idx = i;
20        show();
21      });
22    });
23  }
24
25  attach('.gallery-thumb', function(n) { return n.getAttribute('data-full'); });
26  attach('.guide-lightbox', function(n) { return n.getAttribute('data-full'); });
27
28  function show() {
29    img.src = images[idx];
30    counter.textContent = (idx + 1) + ' / ' + images.length;
31    lb.classList.add('active');
32    document.body.style.overflow = 'hidden';
33  }
34
35  function hide() {
36    lb.classList.remove('active');
37    document.body.style.overflow = '';
38  }
39
40  lb.querySelector('.lightbox-close').addEventListener('click', hide);
41  lb.querySelector('.lightbox-prev').addEventListener('click', function(e) {
42    e.stopPropagation();
43    idx = (idx - 1 + images.length) % images.length;
44    show();
45  });
46  lb.querySelector('.lightbox-next').addEventListener('click', function(e) {
47    e.stopPropagation();
48    idx = (idx + 1) % images.length;
49    show();
50  });
51  lb.addEventListener('click', function(e) {
52    if (e.target === lb) hide();
53  });
54  document.addEventListener('keydown', function(e) {
55    if (!lb.classList.contains('active')) return;
56    if (e.key === 'Escape') hide();
57    if (e.key === 'ArrowLeft') { idx = (idx - 1 + images.length) % images.length; show(); }
58    if (e.key === 'ArrowRight') { idx = (idx + 1) % images.length; show(); }
59  });
60})();