Partial Problem With Posting An Image On User's Facebook Wall

Hi all, I seem to have an issue with Facebook connect API when I try to post a picture.  I have set up and configured my facebook app and Corona SDK apparently correctly, and in fact I can post from my iPad when I run the beta of my game.  However none of my beta testers can post a picture on their Facebook wall, via my app. I am not really a networking expert and I am hoping that some one can direct me to find what the issue might be (has it happened to you as well?)