For the record I copy the answer I gave you through our help system:
Individual images are displayed in all modern skins (as in all modern web applications) by the underlying javascript upon user interaction. This means an individual picture is not the initial state of the web page. When you see a picture in the lightbox it's an internal state of the web application. So when you try to share an individual picture you need to send an extra data to Facebook which identifies the actual image. However after the 2016 US elections Facebook has banned sharing such information - they referred to the risk of "newsfeed manipulation". You can only share now the initial state of a page. They promised to provide some solution, still I'm not aware they did.
The URL format of Twitter sharing has changed a few months ago. Good you reminded me, I will fix if in my skins ASAP.
The Facebook page ID is not the app ID, it's the name of the Facebook page you manage. It must be a "Page", not a personal account. The ID is like "jAlbumFrog" at
https://www.facebook.com/jAlbumFrog