Q: Thumbnails of jpeg don't display

Hey!
Having a weird problem: after updating OS from snow leopard and all Adobe apps, some of JPEG files thumbnails don't display in finder. I noticed, that it's JPEGs that had been saved from Adobe Photoshop. The other ones (even from the same folder) are fine. Also it opens no problem by preview app and other programs, just instead of thumbnail I see a generic icon.
Sounds that it's not that important, but when you have thousands of pictures - it's  critical.

Tried to turn on/off "show preview", no result, tried to find file com.apple.finder.plist as some people suggested, but there's no such a file in ~/Library/Preferences directory

Any ideas? Thanks in advance!