Not sure I dig how this workaround to “galleries” failing in this template looks (doesn’t show the whole image . . .), but that “slideshow” option is pretty cool—lets you click through one by one. For anyone with that kind of time. Anyway, if somebody knows a better gallerymaker, or how to make “galleries” work again in a 2017 WP template, let me know, I’ll implement . . .
Oh, and: how to get the slideshow clicking. Click “slideshow,” then click the image it gives you. That’s when the side-to-side arrows show up.