Header Image Change-Graphene/Weaver-How to

I have tried both the Graphene and Weaver Xtreme or Weaver II templates on a site but want to put a custom header image on them. I always have but when I go to customize… add image… nothing happens. I have uploaded my banner into Media, added on posts or pages as a featured image larger than the header size. I cannot in any way change the header image to my custom one. I can only change the image with other suggested images on the main page. I get get it on any other page or post page but not on the main page.