Removing aspect ratios on grid: simple galleries

Hi,

I was wondering if anyone knows how to remove the forced aspect ratios when using the grid:simple gallery type. I would like to use this so I can control the number of images I show in a row, vs the grid:strips option, but my images are in a variety of aspect ratios so those fixed options don't really work for what I would like to do. I currently have the personal plan so looking for something that is site wide as I can't add code to individual pages. Any help would be much appreciated! 

here's a link to my site: https://mathewscott.com 

Thank you!

For Selected Work page?

Hi Tuanphan, thanks for the reply! No, that is just my index page. Since posting this I have hidden the gallery in question until I can get it sorted out. You can see that page at https://mathewscott.com/archive. They are all set at 1:1, but I would love to have them all displayed in their native aspect ratios while still using that simple grid layout. 

If I can find a solution, I would like to change all my gallery pages to grid format.