Featured Image Landscape Only?

Hello. I set each post up with a featured image, but the posts with portrait sized thumbnails squish the image (versus the images that are landscape which the thumbnails are normal). See attached.

Can you only use landscape photos for the feature image in this theme? I just want it to crop my photo automatically. Is there a way? I know I can probably resize each image I want to use, but that isn’t the easiest solution.

Thanks.