The trick is to crop your first image into a square yourself. Use something like GIMP, Photoshop, Photoscape etc. to crop just the first picture of your listing. The first picture is the only one that's auto cropped, and if you crop it to a square, it won't really be cropped at all by Etsy. So, while you can't really control how Etsy crops the photo, you can crop it yourself so Etsy doesn't have to. That make sense?