That is a good point, Sue, but that thumbnail is a rather extreme panoramic crop so most thumbnails would actually be a lot larger. And if a photographer posts a pano crop, hasn't he or she then already made an informed choice on how to represent the image? Why should a computer algorithm arbitrarily cut the center of that image out and make a square crop against the photographers wishes? If you like your images square, you will probably cut them that way in the first place?
Wouldn't it then be better to atleast let the photographer choose which square of the image to use as I suggested? Wouldn't it also be easier to see on a small screen as the main subject would have a greater chance to show within the boundaries of said square?
I'm not a programmer, but I think there also are many ways to adapt a layout according to the screen size or device used, but of course this takes some additional effort so is unfortunately time consuming. One could even have an option in preferences to let the viewer select if they want to see square thumbnails or prefer the images as shot. It's not impossible and actually many photo sites manages to show thumbnails very well without cropping the photographers images to a square. This is another and of course very, very well known example of how it can look without adding extra padding around images:
https://www.flickr.com/explore
