What is your goal?
posting image in my facebook feed by wordpress
What is the problem?
I Have issue posting image on facebook post by wordpress.
Screenshots: scenario setup, module configuration, errors
Try to make a manual test first, by getting a URL from your wordpress (that you known it exist) and use that link to post in facebook. If you are not able to see the picture, probably your wordpress installation is protecting the picture. But if you are able to see the picture in facebook, then you have to debug the problem (that could be a different URL).
Alternativately you can use a free cloudinary account to upload the picture in case your wordpress installation doesn’t allow you to get the picture. And once is posted just delete the picture from Cloudinary.