Caching of dynamic images

[Neal Terrell]

I'm having a world of trouble wrestling with ASP.NET's caching system.
I have an ASPX page that produces a JPG image on the Response output
stream, and this image is embedded in another page. The image is
generated based on an XML file on the web server that periodically
changes in response to a remote application.

I have been completely unsuccessful in making the generated image
reflect udpates to the XML file. I've tried setting a variety of
cache-related options (SetCacheability to NoCache; the @OutputCache
directive; Response.Expires=0; and an HttpCacheValidateHandler) on the
image's ASPX page with no avail. I've also tried setting these options
on the page that embeds the generated image, but again, no difference.
Finally, I switched everything around so that the image page saves its
output to a file, which is then linked like normal in the host page...
but still no change. In fact, the only way I've found to see the
updated image on my browser is to reset the web application by
re-uploading the Web.config file. Otherwise, I continue to see the
first image generated by the ASPX page, seemingly regardless of the
time waited (including waiting several hours).

Can anyone help with this problem? Ideally I'd want the image to be
re-generated every five minutes.