That page doesn't have an Open Graph image tag on it anywhere. Can you let me know what type of content that page is? Joomla article, K2, Zoo, etc? We have open graph integration plugins for Joomla content and K2, but haven't developed one for Zoo and a few other CCK's yet. That's in the pipeline.
One thing you can always do is add the image tag manually with the following JFBConnect Easy Tag:
{SCOpenGraph image=http://yoursite.com/link-to-image.jpg}
Just place that in the article contents, and JFBConnect will set the proper Open Graph tag.
I hope that helps get you started, but let me know the extension you're using and we'll help however more we can.
Thanks,
Alex