After upgrading to 4.4, when I share a post via URL to Facebook, G+, the "Featured Image" shows as a blank white image on the Facebook post. Looks fine on the Wordpress site.
Some testing shows that Wordpress sends the full resolution photo to Facebook, so maybe it's too large for Facebook?
I suspect something changes in the way Wordpress shares images with the new Responsive image feature in 4.4x .
Here's my facebook home, look for the post labelled "Test Post" about Mac & Cheese.