@porsupah I'm guessing it was memory leak coinciding with an infinite loop, or something. No repro when I tried setting it again, though.
The file in question is 2100x1275px, with 12 layers. Shouldn't be enough to trigger that kind of runaway leak though, GIMP doesn't even use half a gig of memory with that file loaded.
@Zauberin Oogh, lack of reproducibility's a pain. That's getting into the realms of race condition fun. ^_^; Should be fine - I know I've loaded very large images pushing the bounds of some formats' dimensions, and GnuIMP's been fine with it.
Gremlins. Def'nitely gremlins.
@porsupah When it first happened, gimp froze for like 10-20 seconds, but then the whole system froze after that. The second time, when the freeze started the whole system froze up almost immediately.
Maybe because that image now has 4 additional layers >.>