Unfortunately, I got it to work only once. And by 'work', I mean, 'lightbox didn't show up, but at least the photo came up in the browser by itself'. And then after that, it went back to its behavior of just flashing a moment of network activity, but having exactly zero effect on what was displayed in the browser. Weird.
I'd love to spend a bit of time to fix it so that folks who know I've used SilverStripe will be able to try it out and have things work nicely. But at this point, I've simply got to get something working, so I'll try my luck at Image Gallery.
i've got it working under 2.3.3 as well. but i have the same issue as cygnet with not showing the navigation between images. tried to hack the css files, but still can't get it to work. i know that i had to install the gallery module to get everything to work correctly on the popup (mainly related to the css buttons on the popup).