add facebook sharing image

When sharing, the image does not look too nice: https://image.prntscr.com/image/-pUUvI7uSMSrGjlaNidHAg.png

If I got it right, the manual for a quick fix can be found here: https://developers.facebook.com/docs/sharing/webmasters#markup

Not sure about the framing, but an image option I'd might suggest trying is https://drive.google.com/file/d/0B_vy0h9jXD8bU2poWVdyRWdjSFk/view?usp=sharing 