An annoyance: clicking an image transitions the tiny image to a bigger size, then it gets replaced with a larger image file. The result is: the image slides bigger (but blurred), then immediately disappears, and reloads slowly from the top down. It's an annoying flash, and the slide to a bigger size was a waste of time.

That seriously needs some optimising. For example: on click, could the bigger image be inserted behind the small one so it's hidden; on load of the bigger image, hide the smaller image; then do the slide-bigger transition with both images together?