Thank you for your advice. I followed it, and while it didnot solve the problem, it gave me some useful clues.

When I turn off IH2, I notice that the img src is different in Opera etc and IE! How bizarre is that? I am at a bit of a loss.

IE is looking in /parts/images (which I fuzzily remember using back in the early stages of making the site), and also sometimes has doubled .jpg.jpg.

Opera/FF have the correct URL.

I have read some other forum posts that were similar, but they didn't solve this problem.

Do you have any intuition as to what might be causing this?

Thank you!
Sasha