Featured image gets cropped

Hi, I set a featured image on a post that is 1140x450px as you recommend for the post slider. It looks fine on the slider. However when the post is opened the image (above the title) is cropped to 690px. see: http://e-kapedani.com/brent-toderian-keynote-at-green-buildings-holland/ How can I use an image that looks good for both the slider and on the post? Is there a way to just make the featured image to resize proportionally on the post? Thanks in advance.