Featured Image

I have been stumped with trying to get my featured image to show. I select it in screen options. I removed it reloaded a new picture under set featured image and it still does not work. Can anyone please help me to get it to work.

I had it working on a different theme I was using when I was using wordpress.com but theme I was using is not available on .org so I selected this minamaze theme and like it. this is the final thing I need to get up and running.

Someone please help.