Image viewing on the forum has been updated and improved.
You can now scroll, zoom, and hide the navigation (previous/next arrows, icons) much more intuitively on both PC and smartphone. On PC, you can also click and drag to move through the images like you do on smartphones, which I really like 'cuz it’s smooth.
In action on smartphone:
You can try it here by clicking on an image:
For the tech-savvy: it uses PhotoSwipe: https://photoswipe.com