Sometimes when you share images on Facebook that are in the body of a post, the following error will occur:
Can't load URL: The domain of this URL isn't included in the app's domains. To be able to load this URL, add all domains and sub-domains of your app to the App Domains field in your app settings.
To solve this, you need to add your domain to your Facebook App, located in the platform's app dashboard. When you open the app, navigate to Settings and then Basic to update the domain in the same screen:
Once your domain is updated, image sharing on Facebook should work without any issues. If you have any questions about this, please email firstname.lastname@example.org.