iceweasel: resize of the picture adds blur places

[only_one_mystery <b.vomocil@gmail.com>]

Hi,
I am using Iceweasel in version 3.5.8 on Debian Testing and I am facing
following problem: it's happened to me many times, that when browsing
Google Picassa web album, some of the pictures are resized (for instance
from 640x427px to 640x426px) and the resizing blurs the picture. But the
resizing isn't because of the small browser window. I've posted more
about the problem in this thread:
http://www.google.com/support/forum/p/Picasa/thread?tid=4ad52fc29cd0d838&hl=en&fid=4ad52fc29cd0d838000484d4a52250c0

I would be very happy, if somebody could tell me, how to disable this
unwanted feature.

Best regards
Breta

P.S.: I hope I chose the right mailling list.