This may be a theme issue, because all of the Open Graph plugins are failing to work.
I have it installed at http://spiritfilleddesigns.com
It is a woocommerce store site, but the theme is not from woo themes.
But the shares are only randomly showing the featured image. But the theme is have overall issues with product images and featured images showing correctly. They say they are coming out with a wc 2.0 compatible update, but still waiting.
But do you have any idea why the plugin would not be working on 100% of the product post pages?