A new day has dawned and I've had time to look at what's what.
In summary it appears to be a Firefox problem.
(i) I've changed my default browser to Edge which has allowed me to upload an image to the Ships thread.
(ii) Re links in Email problem.
Up until a couple of weeks ago, links in notification Emails always opened up the page with the correct colour scheme and no necessity to sign in, even if I didn't already have the Cellar open in my browser. (I don't sign out).
Clicking on one of these links (example below) in Edge opens up the page in the same manner as Firefox once did.
http://cellar.org/showthread.php?t=4657&goto=newpost
I'm not that keen on Edge but, if it reduces the hassle factor, I'll stay with it.
Thanks everyone for help and suggestions.
