Products’ pictures size

Hello,
I’ve problem with products’ pictures. They are in different sizes and most of them are not square. I’ve been trying many solutions but none of them worked. I’m including the site in post. As you can see, there are pictures, that have rectangle size. I would like to find a programme that would make them all to square (of course no only crop, but resize the rectangle to square). Or maybe there is other solution for problem like this.
Ofc I could do it by resizing all of them manually, however there are almost 2k products.

Thanks in advance!

The page I need help with: [log in to see the link]