There's an ugly delay + flickering when using the autostart parameter in conjunction with the image parameter. The problem happens because the player waits for the image to be completely loaded and only then it will trigger the autostart.
IMHO, the player should REALLY autostart, without waiting for the image to be loaded, but this image should also be loaded in background to show it when the movie finishes.
We're already investigating this. I've added your remark on the autostart:
http://developer.longtailvideo.com/trac/ticket/1183