I wrote that this worked. It did. But just for one day!? Weird.
Now I am stuck with the oversized avatars in the article headers again.
I
From the displayed page source I believe the class is "avatar img-circle"? Correct?
I redefined both in my custom.css but this seems to have no effect all of a sudden.
Can you clarify which css file and which classes need to be edited to control the size of the avatar in author/ article headers?
Seems if I muck about about with the template's GUI "customizer" changes hard coded into custom.css are overwritten. Which explains why my first attempt worked briefly.
Anyway, your suggestions has fixed it. I'll avoid fiddling with the template now :-)