Featured Image in Post linked to Page ?

I have a page that contains a NextGEN gallery, the page uses a Gallery Template page that I have made.
I also have a post that contains a featured image that I’m trying to use to link to the page with the NextGEN gallery.
I have added the featured image from the Media Library, in the Media Library window I have tried to put the url of the NextGEN page in the Link URL field. This doesn’t work. Is it possible to do this or am I doing it wrong.