Right, sorry. I was using test images (hence thinking they were squares) and also not explaining myself correctly.
What I’d like to do is have a different size for related product images than the product thumbnail default. We use large images for our main product thumb so having them show up the full size is too large. I can force it with CSS, of course, but an option for a Related Products thumb in the admin page would be nice.
see http://jenniefresa.com/shop/products-page/lips/super-gloss/ for an example.