centering/sizing vertical photo

Hello, I've used a vertical photo as a featured image on blog; I thought I'd finally figured out sizing from the theme directions, but now the photo isn't centered and/or isn't big enough. I still might not have the sizing correct: Featured Image: Excerpt Featured Image Width: 860px Height: 484px Is there a width/height for vertical that would correct the problem? Or a way to center the image over the post? http://quintinellisonphotography.com