Is there a way, when I write a post, to have the Featured Image thumbnail on the main page and when you click on that post, it's fullsize in the post? I don't want it to be a thumbnail when you are in that specific post. I tried to "add an image" to the post (fullsize) as well as having the Featured Image, but that picture was visible on the main page as well. That is not what I want.
Is it theme specific?