I want to include a specific graphic as a sub header to a specific catagory

I want to place a sub-header at the top of a specific category that will display when the category is selected at the top of the category. I would like to make this option available for all categories and savable so the image object would be saved when the category is created. what documents do I need to edit to make this a possibility. I have been adding a header to the latest document which then has to be edited and removed when a new document is created and added to the new document which works but is idiotic. I haven’t found any plug-ins that handle this either. also using the Genesis feature post widget allows for ordering the posts but when calling the category directly the order is reversed so the item that is the oldest always comes up last. not an issue but it means I am always moving the header. can anyone help me add a header to the category function. or at least point me in the right direction. we are up to 15 wordpress sites now and this would really make my life easier.