auth_request with vhost conf files

[lsces]

Thanks Francis ...

Your prods have pointed me in the right direction.  My initial problem was
not being able to include a parameter in the auth_request and that is where
the examples brought up the proxy_pass 'solution' ... of cause what I was
missing is that the request for the images are already independent requests,
so there is no problem simply calling php-fpm directly.

The 'localhost' question is a red herring as php-fpm simply uses the correct
root while my proxy_pass setup was using the 'default' localhost settings
... I'm getting my head around the various twists and turns but finding
examples that cross the various boundaries is difficult. I will run a crib
sheet once I've tidied up what I do have, but my less than optimal setup is
working on three sites currently.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,287570,287602#msg-287602