ChristinaShoe on "Featured Image not Displaying in Facebook Share"

In the past few days when someone shares one of my posts on Facebook the featured image does not display. It's just a white box with my URL under it. It was working fine before. And this started occurring BEFORE I updated my WP version so that's not it. Can someone please help? I am not a developer so I'll need pretty specific instructions please. Thank you!

Run a link to one of your posts through the Facebook Debugger:

https://developers.facebook.com/tools/debug/

I did and it says that the share app ID is missing?

I did and it says that the share app ID is missing?

That's not a useful think. Did you see it reference an og:image tag? That's what it would pull in as an image.

Okay well this is interesting. It's trying to pull up http://thewholecook.com/wp-content/uploads/2016/06/In-Defense-of-Mom-Style-Featured-Image.jpg (which gets an error) but when I go to the blog post itself and click on that image the actual URL is http://thewholecook.com/wp-content/uploads/2016/06/In-Defense-of-Mommy-Style-FEATURED.jpg.

I don't know why this would happen? Up until a few days ago this shared perfectly on Facebook.

I checked a second blog post in the debugger and got a different issue. The debugger for this post doesn't pull up any blog post excerpt and it shows no URL (right or wrong) for an image. It's just blank.