I'm now looking at Macromedia's Flash format. Its intended as a vector animation format, but it appears to support JPEG bitmaps. Also under consideration is a contorted client-side pull application, but I'm not sure IE will be able to stop pulling when the image ends. I limit the buffering in the program and OS so the frame generation rate is guided by your comm link. The digitizing rate automatically adapts to your speeds without me writing code.
Unwritten code is always the best.
I send the frames at low quality except for the final frame, which is sent at a medium quality. Its even neater now. I send reduced resolution images during the ball spinning portion then progressively increase the quality as the image stabilizes. Everyone gets their own destiny. If someone is using the 8ball you will be queued and get an image showing your position in the queue.