My featured images are being cropped

[ Moderator note: moved to How-to and Troubleshooting. ]

Hi,

Hoping someone could help. The featured images on my home page are all cropped and look terrible. I have been trying to fix this for the last week. Have been trying changes in the settings-media tab but nothing has changed.

Also have installed the thumbnail editor plugin and followed the steps exactly but my images haven;t changed? Do all images have to be reuploaded after changes made to thumbnail editor?

This is my site:

http://www.cantillonkitchen.com/

Please help!!!