I have tried everything I know to try to get Pocket IE on the iPaq to refresh an image on a page when a page is hyperlinked back to. None of it works. I've tried every HTTP header I can find on both the page and the graphic. It seems that once Pocket IE grabs an image, for performance reasons it assumes that the image never changes, unless you physically tap the refresh button on the browser. It ignores every no-cache HTTP header, every expires, every max-age, whatever. There doesn't seem to be any way under the control of the web server to flush the cached image.
I don't really expect anyone to have any ideas here, but I thought I'd throw it out. If anyone does have any ideas here, I'd be very grateful. I've spent maybe 8 hours on this so far.