Hi! I managed to do what I wanted by overriding product-image.php so I am on the right path.
I converted all thumbnail pics to 200 x 200px, hope it is good. Also It is possible to:

1. Extend the page width like in the site from attach?
2. Border products with space between like in the site from attach?
3. How can I properly solve the issue of a title having one line and another is two lines resulting is a messy product grid?

Thank you!