I fixed the resizing bug, but was unable to reproduce the right alignment bug you're talking about. What I tried was using an image with handleOversize set to "resize". I tried both IE6 and 7. Do you have a sample page that demonstrates the problem you're talking about? I haven't pushed updated the code with the resizing fix because I'd like to investigate this issue a bit further and push it out all at once.
Ignore my oversight. It was actually a CSS conflict that was causing the right alignment. I confused it for a shadowbox bug because I was testing the resize issue and noticed that it was right aligned in IE6 and 7 but not IE8. I figured they were related without actually verifying that.