I used to be running Xubuntu 12.10, and I just upgraded to Xubuntu 13.04 (phew, that took a while...)
The first thing I noticed after logging in to my account was that the thumbnails were missing! I checked in the desktop properties:
and thumbnails were enabled. Yet my desktop looked like this:
Thumbnails are still seen in Thunar, though:
What is the problem here? Any ideas?