There’s an option to show the featured image automatically in each post.
But one caveat: it’s going to be there for every single post–whether you want it or not.
It’s a great feature IF you’d like to have a thumbnail image of your featured image in each (and every) post. You can format it to the dimensions you like and even choose how to align it–but it’s going to be that way for every post. Consistency? Absolutely! Room for change? Uh, no.
So if you’d like to Set It and Forget It and have a consistent look, this is the checkbox for you. If you’d like some more control of how your images show up in individual posts, then uncheck that box.