I have to wonder how many people are falling for these things at this point. I mean, they're actually hiring some halfway smart programmers here, as they try to stay a step ahead of the spam filters, and they're working hard -- I can see the spam tech evolving week by week...
Edit: Okay, not quite as smart as I thought -- upon closer inspection, it's still all a single GIF, that just happens to render bit by bit for no apparent reason. So the final frame is still the same as the previous round of spam tech; shouldn't take long for the anti-spam forces to catch. But I suspect they'll think of the many-little-images version soon...