I have installed the IE8 fix that switches the system automatically to use IE8 in compatibility mode.
When I use this switch I have the same issue as you do, the first image displays ok, the second displays to the right (mine are also 800 wide) leaving the first in place, and the rest follow this pattern.
If I turn of the compatibility plugin so the browser defaults to IE8 (which I am using) it shows the very same issue.
I have tried what I can think of but cant get it resolved.
Can see it here (banner under main top menu) rotates every 6 seconds
http://www.kbcnetworks.co.uk/kbcnw