–Deactivating all other plugins, including caches, had no effect; when I upload photos, I still get broken links where the photos should be. Cleared cache.
–I did not switch themes, as I have never done it before and I wouldn’t know how to get the old theme back.
— I now suspect my theme, WordPress Theme 1135, may be the culprit as I acquired it in 2011 and had my provider at the time alter the theme to my specifications. My trouble began when I updated WordPress from 3.2.1 to 4.5.2. I imagine the old theme is incompatible with the new WordPress version in many ways. My site no longer accepts comments. I have my current host liquidweb looking into this, but I have a feeling I’ll have to rip out the theme and use another one. However the site is massive and I have no idea how to install an updated theme.
One more problem with nextgen: to add photos to a gallery you can’t pick them out from a list in Manage Galleries as you had before, you have to scroll through a list of galleries with just the names, not the numbers. Since I hve over 8700 galleries that takes awhile.
Until I get the nextgen problems cleared up I have switched to Responsive, with which I’m not completely happy either.