Well, it's a new day ... and I've tried using "Manage Attachments" and the 'landscape' icon. Both lead to the same screen .. which doesn't work for me.

I finally achieved a screenshot, but it took nearly a minute to load that pop-up properly and generate (a) the 3rd button ['My Albums'], and (b) activate the 'Cancel' button and other features. And now, after that one success, it's refusing to do any more! The 'page refresh/loading' bar just stalls at around 15% and then freezes

System is Mac (OS Catalina) with Safari, clocking 77 mbps download via fibre cable.

(Edit: After leaving it for a while, I can finally download the screenshot of the whole page! )