Main product image cropped

On the product detail I want the featured image to be 620×420.

The best I can achieve is 600×420 – so even though I have updated the column sizes it crops off 20 pixels of the width.

If I right click and view the image it shows all the image.

If I click the preview magnifying glass again it shows the whole thing.

So far I have only done this to update the column sizes:

.woocommerce div.product .images {
    width: 60%;
}
.woocommerce div.product .summary {
    width: 36%;
}

what else do I need to do so the image does not crop?

Thank you for your time – Jason