How to make gallery with two columns

Site URL: https://www.andrewseidlerphoto.com/ocean

I have a website to display my photography. I currently have both horizontal and vertical oriented pictures that need to be displayed in the same gallery. I have been using the Gallery Grid: Strips style of gallery that way there is no cropping done. However on different screen sizes the the layout changes. I was wondering if anyone knew some css to make it so the gallery will always display two pictures in a row. In other words I want the gallery to always show two columns of pictures without any cropping. It's fine if it adjusts the image scale to make it fit but I don't want it to crop. 

The site link above is to an example of one of my current galleries.

Any help would be great. Even if it's not possible it'd be nice to know so I can stop trying. Thank you

This is not possible. If you agree, we can give the code to change mobile to grid simple, thus you can change to 2 columns/