Grid cells are too small

[melTr]

This is about Bulma.

Overview of the problem

This is about the Bulma CSS framework
I'm using Bulma version [1.0.1]
I am sure this issue is not a duplicate

Description

I tried both versions of grids but I'm not able to get what I need : a grid of pictures.
Using smart grid, even at is-col-min-12, the images are too small. I will need a 32rem. But I don't see possibility to change via sass variables?
By using fixed grid with 3 columns, I found the column gap too small. But it seems I can't use is-column-gap-x?

Expected behavior

Grid with bigger images.

Thanks!

[jgthms]

I'm increasing the number to 32, which is a maximum of 768px.