IIS 7.5 and images not being cached

Question

I cannot get the image files to cache. I have tried everything that I have found on this site and others and still cannot get them to cache.

Web config setting that

Answer 1

In case anyone needs to configure your site as Chrome Audits or GTMetrix require I've configured my environments with the following (thanks to Marco's answer):

using 365 days and both tools took that value as acceptable for a cache time.