I wonder if anyone encountered similar case as I'm having now. I'm using Drupal for FaceBook and Open Graph Meta Tag to make posting on to a FaceBook Page. The FaceBook debugger (https://developers.facebook.com/tools/debug) seems get every meta tags all right, including og:image. and I can successfully make the post on the FB page--the only problem is that the image does not show.
I browsed through the internet, found someone had problems when the image size is either too big or too small--but it seems not my case. I tried several different image sizes, none of them work. Besides the fb debugger tool, is there any other tools to debug?