When I test my post page on Facebook Debugger I get no errors and no warnings, and it grabs the right thumbnail besides the default one.
That’s the result I want when I would share my post on facebook, but it doesn’t happen.
How can fix this strange annoying problem?
This is an example link page related to my issue:
http://www.moroccoenglish.com/vocabulary-works-make-or-do/
I have faced the same problem. After changing the og:image to a bigger one, everything solved. I think og:image should be bigger than 250 x250. Also noticed you have declared og:image two times with two different images.