Sorry about that. I was trying to show you where to add the code. That’s not the actual site I’m working on.
Your edit won’t push through because there’s a problem with your WordPress setup. Please check your wp-config.php if you’ve setup the security salts. Please contact your host if you need help with that.

As previously said, the code works on my end.
To add the border, you need to add this code in Appearance > Theme Options > Global CSS
.woocommerce div.product .images figure [data-thumb] {
padding: 5px;
border: 1px solid #ddd;
}

Please have a developer or your host fix your WordPress setup so the code I gave will work on your end.
Thank you for understanding.