I'm not sure if this is a DNS-323 issue or not, but I figured I'd try here first. My 323 has 2x Seagate 1.5TB drives in it (and the drives DO have the upgraded firmware from Seagate per another issue with the 323).
I moved our 15GB worth of digits photos to the 323 and mapped a folder Y:\Photos\ to our Vista laptop.
In Windows Explorer on Vista 32 Home Premium, when I open a photo folder, it'll take some time to load all the thumbnails, but when they do finally load, 95% of the thumbnails vanish and change to the windows default icon for .jpg. If I reload, it'll do the same thing - but a different random set will change to the default icon. This does not seem to happen on a local drive like My Pictures.
In Picasa, all of a sudden all of my 2009\ folders vanished from the Picasa Folder List, as well as about 50% of the folders from 2008\, 2007\ etc. I checked Picasa's list of watched folders and Y:\Photos\ was still there (though it seemed to take an inordinately long time for Picasa to produce a drive list). I uninstalled Picasa, removed it's database, rebooted, reinstalled and now it will only show about 10 random folders out of maybe 500 on Y:\Photos\.
I was looking through the 323's config - I do have Jumbo Frame set to off. Should these been enabled for the Seagate 1.5TB drives?