Thank you very much. It only works if I share it like this: example.hu/wallposts. Not working: https://example.hu/wallposts.

You need to post again. Debug it here https://developers.facebook.com/tools/debug/

Does it appear properly on Facebook? I still have a blank white image.

Working fine

Now this is what the end of the file looks like, and yet there is no preview image, although if I open the link, the image appears there.
echo '</div>';
?>
<meta property="og:image" content="https://webpage.hu/viev.jpg"/

On that post there are many images what image you wanted to add?
Simply edit view.php of this component and add at end

?>
<meta property="og:image" content="https://path to image" />

I think an image is needed when the mydomain/wallposts post is published on Facebook.

Works great with OSSN 5.6 too! Many thanks Arsalan!

Hello Arslan I hope you are doing well.
I wonder if there is a possibility to improve this component so as to display the blogs also so that the public content will be richer. I also noticed a small Bug, when we add a new blog, there are an empty record {"post":"null:data"} which is inserted into the database and it creates an empty posts in the display of '/wallposts'. Have a good day

Thanks, amazing work as always!