//Off Topic: The embedded image (in post body) downloaded (somewhat unexpected,) whereas the thumbnail below (attachment area) opened in preview window (whatever you call the large image on screen that can close and still be on post page.... lightbox?)
That's because the one has content-disposition inline (i.e. in browser) and the other attachment (i.e. download). Note that the links are different.
Huh, on my desktop I got content disposition inline but on mobile I get a prompt for both (dunno about headers)
Yes, I put a "note-to-self" in another topic... who know which one. xD (<= yet another reason for 1-bug-1-topic)
Anyway, yes: the URL in ILA lacks the "image" parameter.
I think at the beginning I added it, though due to the fact that it creates few problems when the attachment is not an images I removed it.
Though, it should be there and properly deal with attachments that are not an image.
/me wonders if this was ever fixed
I guess so with the lightbox-like overlay.
I have long stopped adding images as ILA using share button. Will try and check.