I used the FB debugger tool to clear my FB cache, as per your instructions above.
Initial invocations of the FB debugger tool produced some weird error messages, which I wanted to print screen and forward to you, but couldn't replicate.
The debugger tool subsequently ran without error but did not immediately update the link image--specified in the WP Settings SFC Default Image option--that accompanies WP blog entries pushed to FB using SFC.
So I waited a few hours, pushed out another blog entry and voila! All my image problems evaporated overnight!
Thanks much, Otto! It's great to have competent technical support at an affordable price. Ha. Ha.
Would like to take you out for a drink, but my guess is we're worlds apart.