Ian, Couch's upload process does not use loopback connections so that is not the problem.
I logged into the admin once again and (as happened before) the upload dialogbox opened up without any trouble. I queued up about fifteen images and this time all, except two, uploaded just fine - you can check. The two that did not reported a 'ERR_CONNECTION_RESET' error as before.
So it seems you server refuses connections when it is under load or something - this is seen very often on shared hosts.
It is definitely not a problem related to the CMS (else we wouldn't be able to upload even the dozen odd images I did just a while back).
I can only suggest that you try a better host.
I logged into the admin once again and (as happened before) the upload dialogbox opened up without any trouble. I queued up about fifteen images and this time all, except two, uploaded just fine - you can check. The two that did not reported a 'ERR_CONNECTION_RESET' error as before.
So it seems you server refuses connections when it is under load or something - this is seen very often on shared hosts.
It is definitely not a problem related to the CMS (else we wouldn't be able to upload even the dozen odd images I did just a while back).
I can only suggest that you try a better host.