Make all Woocommerce thumbnails and images square with no cropping

On my 'i4u' site I'd like to make all Woocommerce thumbnails and images square with no cropping. Essentially I'd like the images within the thumbnail resized so that 'fit' into the square image without chopping anything off. I tried using some code i found on here and then regenerating thumbnails, but it didn't work.

I'm attaching a screenshot of what I'm looking to achieve.

Thank you guys!