Mu thumbnail previews were working fine a few days ago. But today when I logged in, I see that any .pdf, .png, or .jpg file thumbnail is not working properly.

I tried quite a few solutions, but none of them worked. These include:

.thumbnails/fail and .thumbnails/normal
Also tried this
 sudo apt-get install libxine1-ffmpeg
(This was already installed)

Log out/restarting after doing all of the above hasn't helped.

And a few other methods I found in threads referring to this site.

Curiously, there are a few .png files in .thumbnails/normal now, just that they aren't being shown.

I'm using Ubuntu 11.04

Will appreciate any help I can get on this.