Update...
Back on my PC now. I deleted the Cellar bookmark and re-instated it with the https version.
I've tried another image upload and this is what I get on the preview:
Edit:
Dammit! The preview shows the file information but the image appears in the post!
That never happened until recently. I was always able to see the complete final version of the post in the preview pane.
The words 'live with it' spring to mind.