Hello, I am using the Graphene theme (at shakeyourfist.com), and cannot get the Featured image for posts, or other pages to be used when I select another image. Only the image for the main page is displayed. I have another blog at http://englishspokenhere.de/ESHblog/, using a different theme, where the featured image works for the different posts and pages…the fix for this is different, as I had the same problem…I think with the Weaver theme. The fix is listed here: http://wordpress.org/support/topic/featured-image-not-working-with-nextgen-gallery?replies=23
Thanks for your help…you should have gotten a donation from us a while ago. I can appreciate how much work it is, even if I cannot do it myself…JK