Weird: Mac turns flickr images invisible?

[hmpf]

No time to reply to comments yet, but I wanted to throw this question out here in case a more Mac-savvy person has an answer to it: today I accessed my flickr account from the Mac I use at work, and about half of my photos seemed to be gone (causing me no small distress, because - of course - my first conclusion was that flickr must have 'lost' half of my pictures). Accessing the account from my laptop at home, though, I can see that all the pictures are still there.

Any idea why I can't see my photos on the Mac?