GK Portfolio – Thumbnail Portfolio Gallery

I have a question. Is there a way to get the thumbnails to crop from the center of the image instead by width? Currently the images have a white border around the image but on the thumbnail gallery preview it shows the white bars but not then entire frame just portions. This makes the images not look uniform in the gallery.

You can see what I mean here.
https://kandyradzinski.com/category/portfolio/paintings

Is there a way to A: have the white border show up around the entire thumbnail image or B: get the image to crop from the center leaving the white borders cropped out in preview?

Thanks!
Jeff