Hi! I have another wrinkle to add to this question. I really appreciate the excellent suggestions from @tuanphan and all.
I would like my product list pages in desktop to display portrait and vertical images not only in their original aspect ratio, but as the same size. (Actually - personally, since my art comes in slightly odd sizes, I would still like to crop the images but display ones tagged "portrait" in portrait orientation. But I can live with using the original aspect ratio and upload cropped thumbnails.)
And then ideally I would like the rows of images to line up on the image centerline. Does this make sense?
My page in progress is here: meownderthal.shop/shop
Thanks!