When I monitor the feed closely I can watch as new images appear at the beginning of the list between each refresh. But what I've noticed is it will, all of a sudden, throw away all the current images and display a completely different list. And then the strange part is shortly later it will revert back to the previous list and go on about its way until the cycle repeats. It also appears that when it jumps to the other list, the images that it returns are ones that were displayed previous (usually around 5-15 minutes ago).
It does this frequently, all throughout the day. I can't pinpoint when exactly it first began, but I know that before a few months ago I never saw this happen.
At first I thought the problem was on my end or a strange caching problem with my ISP, but I've been able to duplicate the problem on different browsers and from different ISPs.
I just thought I'd bring this to someone's attention, as this behavior makes it much less useful to me.
I'd also like to thank Live Journal for providing these kinds of backend data-mining feeds, they provide for some very interesting data that I've never seen available from anybody else on the net.