Most of the time I post images via links to the source so I don't really have a way to tell DU which size. It is whatever the source provides - and DU does limit the actual size on the page.
When I move an image to a hosting site (such as imgur.com), I also don't usually worry about resizing before storing. Rarely I'll crop an image to focus on the subject at hand.
As a counter-example, I just posted this from JoJoFromJerz's substack and it could have benefited from resizing, but at the same time I thought the "old-fashioned" look of the photo gave it a certain realism for that time.
And this one from the same substack article is more "modern" looking.
(From https://www.democraticunderground.com/100221096830)
Note that DU rendered both of these images based on some internal parameters.
Edit history
= new reply since forum marked as read