nautilus doesn't display all thumbnails

["Carl R. Brune" <brune ohio edu>]

When I browse a folder containing jpeg images nautilus only
display some of the thumbnails. For the files which are not displayed
an icon that looks like a clock or timer is displayed, but the thumbnails
never come. I don't see any logic to it. Nautilus knows what type of
file they are if I do a right-click/properties. I have also looked
under preferences/preview, all files under 10MB should be shown --
this covers all the jpgs I have.

Please advise. I'm running Nautilus 2.10.0 under
Fedora Core 4 (did a yum update 8 days ago).

Thanks,

Carl B.