Have you ever tried to change your Facebook post thumbnail when posting from WordPress, but it looks strange or doesn't even show up at all?
Step One - Where the magic happens.
Step Two - Create/add your thumbnail image.
Step Three - Edit your post.
This is where you’ll insert the image you want to use as a Facebook thumbnail.
Step Four - Validation
Before linking to your post on Facebook, you need to complete one more step.
Validating and testing your Facebook post ensures that you’ve done everything correctly and that it will properly post.
But how do you do that without posting? Well, Facebook provides a free resource to do just that.