Featured images

I have a question for you, how can i move, replace a featured image in a post on my newspage? Now wordpress uses the center of the image, but if I have a picture in portrait, the head of the person appears not in the post. And that's a bit a strange sight. I have also the problem with post that i still featured images have to use in my posts on my newspage, otherwise the pictures dont appear. Can you help me with this issues? My newspage: https://foto-wp.be/nieuws/