@PhilipStewart Did you ever figure this out? It would be a nice feature to have. I'm looking for the same functionality for an artist who is selling prints. It looks like you've just kept the 1:1 aspect for now.
One thought I just had is to sort the prints into categories like "horizontal" and "vertical" or "landscape" and "portrait" orientation. Then, you could add two summary blocks, one showing the horizontal category with an appropriate aspect ratio, followed by the vertical category with its ratio. This should work well if all of your horizontal images are more or less the same ratio, and same with vertical. Let me know if you think of another solution!