GNOME background being imposed on another background

I would also like to add that the background is stuck (not changing) and nautilus is using 2.1 GB of RAM with no nautilus windows open (although I did do some large searches recently with it.)

Thank you for your bug report, the issue is not clear from the description though

Please take a look at the image I attached, and then take a look at the two images:
/usr/share/backgrounds/cosmos/sombrero.jpg
/usr/share/backgrounds/cosmos/whirlpoop.jpg

whoops, I meant /usr/share/backgrounds/cosmos/whirlpool.jpg

I'm getting this too. Changing to another background and back fixes it, until it happens again.

My PC is 32-bit though.

Also, maybe related, my computer's idle time is no longer reported after a while, thus my screensaver no longer fires, until I log out and back in.

Thank you for helping with making Ubuntu and Nautilus better by reporting this bug.
Do the wallpapers get stuck right away, or only after your system has been running for a while already? If you could find anything in /var/log/messages related to this I would be most grateful, but just more information on what causes the slideshow to get stuck would be enough as well.

For me, it happens after a long while. It has not happened lately though. The only items I found in the messages log from the day I reported it (and 24 hours prior) are what follows:

Nov 26 07:50:53 scott-laptop rsyslogd: [origin software="rsyslogd" swVersion="4.2.0" x-pid="918" x-info="http://www.rsyslog.com"] rsyslogd was HUPed, type 'lightweight'.
Nov 26 09:02:22 scott-laptop pulseaudio[18510]: ratelimit.c: 102 events suppressed

I see that pulseaudio a lot (?) even now but don't think it's related.

I've reported the issue upstream with a request for help and I hope the developers of Nautilus will be able to provide us with some clues. If you've got more information, please add it.