Featured Image resize question

[lwolfe63]

I need help! I am trying to modify the Adapt child theme that was built on the Genesis framework. It has four featured post/page widgeted areas under the slider. I modified the theme so that there are only three columns. I changed the CSS and added the new size for the image too. I am obviously missing something because when I upload the featured image, it doesn't come out to the new size. Would someone please help point me in the right direction? The website is http://www.bohochicyoga.com - you can see that the featured images under the slider are aligned too far left and the images are too small.

Thanks in advance for your help. The forums have been such a huge help to me.