Publicize not pulling through feature image

Hi

Whenever I publish a new blog and use Publicize to post to Facebook, Twitter and LinkedIn the link appears but no feature image; just a grey person image.

The Facebook debugger does not show any issues.

https://developers.facebook.com/tools/debug/og/object?q=http%3A%2F%2Fwp.me%2Fp33RVD-1am

Please can you help me.

Thanks

Gary