I finally received an answer from Booty as to what the problem is. And I quote her:
"The gallery is an ongoing problem that requires work by a developer. I'm not one, and even though sometimes I say to myself 'Self, that would be a worthwhile skill', I then come to my senses. So, anyway, until one of the developers here comes up for air and can tend to it, the gallery is on hiatus."
It's not good news, but at least we now know what the problem is.