Help sizing CMS content (with varying aspect ratios) to fill div

I am struggling with something that I am not sure is possible.

I would like to create a page that draws various items fro a collection list “paintings”. What I would like to happen is for the CMS to pull The main image from every painting in the collection list and display along side it the 4 detail images in a 2 x 2 grid. This is partially happening. The problem that I am running into is that i would like the main image to be equal in height to the grid of the 4 detailed images next to it and I would like the elements together to span the width of the page. The main images are not all the same aspect ratio, So I cannot specify fixed widths (as I have currently done) as the main image would need to be scaled depending on its aspect ratio.

I am including some sketches of what I would like to achieve:

Here is my site Read-Only:
(how to share your site Read-Only link)

I still haven’t figured this out. Did I do a poor job of explaining the issue? Or is this something that is very difficult to achieve?