Adjust the item size

Hello, I’ve tried to arrange the size of the thumbnails, I’ve noticed that from paramenters.php there are values https://www.screencast.com/t/K8KLjKKK

However, if I put these values, the grid will not be responsive on lower resolutions, it will create some borders and I cannot manage to remove them from css https://www.screencast.com/t/BqffpbhdiXz

Because it creates the left/top from position absolute.