Well, it took 30 posts in until 404 showed up for me on my end.
So, it looks like the thumbnail creation is lagging during the posting event since that one has the full size on 128ducks (click to enlarge and it's there).
However, I've seen some where even the 128ducks one comes up as 404 when you open it a new tab.
A little bit of everything kinda borkery I guess.
Oh, and the lag is really bad on my end - anyone else as well?