I'm only answering because no body else did, but I don't have too much to offer...
It's probably presenting just a picture file to the browser, and IE just says, ok, you want to save or open this file... the other browsers interpret that as oh, I can display this, so they do.
If you can somehow wrap some simple <HTML> tags or com .image something code around it to say to IE - render this in your own window, don't treat it as a downloaded file, then I guess it should work?
Sorry, not that helpful I know.