I got some great help from @Thai regarding a button that opens a lightbox both on desktop and mobile about 3 weeks ago. It worked great up until we moved content from our dev site to our live site, which is now at www.pulstar-mfg.com/about-pulstar.
All of the HTML, CSS, and JS is the same as what @Thai suggested. Any idea why the images don’t appear in a light box when you click on the button and why the image gallery is no longer hidden?