Metacity theme preview image is currupted: http://bugzilla.gnome.org/show_bug.cgi?id=104837
I first saw this bug when gnome-theme-manager became part of the gnome-control-center package a few days ago, but I hadn't reported it because the latest upstream version of libmetacity hadn't reached Debian yet. Now I've upgraded to metacity 2.4.21 and the bug is still there. This must be rare if it wasn't already reported, because it is very obviously a bug. Are any other Debian users seeing this? I especially want to hear from other Debian/powerpc users, because this seems likely to be a bigendian problem.

