Thumbnailsize in WP gallery

Dear reader,

I would love for my gallery thumbnails to be square.
My thumbnail settings are square, but they are not in my gallery. I have had this before in a different theme (different website) , i had to delete some code from my functions.php. Tho on this theme i can not find any code that makes my thumbnails not square.

Where is this code hiding? How can i make my galley apair square.

Thank you so much.

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