No thumbnails in shared folders

Hi!

I have a question regarding shared folders. If I put jpegs in it, and then
open the folder in either Windows Explorer or the shared folders application
from messenger, I can see the preview images for a second and then only the
generic jpeg-image from Vista. Is there any way to display jpegs as
thumbnails? Jpeg-thumbnails work in every other folder just fine, and the
miniature preview of, for example, a word document also works in the shared
folder...

I am running Vista Home Premium 32bit, with Live Messenger 8.5 latest beta.

Thanks!

Haplo