I'm pulling my hair out trying to get Facebook to show a preview image for my wordpress posts when the link is shared. Sometimes it shows, sometimes it doesn't. It's very arbitrary. I tried using your pluign to fix the problem... but it's not working.
On further investigation I found that your og:image meta tag has invalid HTML.
This is the page I'm trying to get working: http://studyweightloss.com/motivation/test/
Put that URL in here and you will see the error: http://validator.w3.org/
Can you please tell me how to fix this... or if it's not the problem please tell me how to ensure my thumbnail preview gets displayed when I share the link on facebook.
P.s I have also run my page through the FB debugger (https://developers.facebook.com/tools/debug) but no errors are appearing.