I have an image on my site that I want listed in Google. So I've tried to include it in my sitemap so Google can easily be aware of it. It's hosted inside a page that's marked NOINDEX (the page is accessible but is overly device-specific and so is not an appropriate entry page). How do I describe this situation in a sitemap?

Currently Google tries to index not only the image but also the hosting page, then complains that a listed page is marked NOINDEX. The page is (or should) NOT be listed, but I can't figure out the syntax for describing the image in my sitemap and pointing to its hosting page, but without that hosting page being available for indexing.