Facebook video calling freezing issue!

When I start a video call on facebook with Google chrome or Safari I experince this issue:

After starting a video call and the other person accepts the call and it starts to load, then once the person is conneted I see a small screen with my webcam's view at the top right corner of my browser but the issue is the big screen also has a frozen view of my webcam (a photo of me when I first got connected to the call) and the other person can see/hear mebut I'm only able to hear him/her without being able to see them!!!

These are my details:

Macbook Pro - 13-inch, Late 2011

Software: Mac OS X Lion 10.7.5 (11G63)

The diffrent browsers I have tried using are:

1-Google Chrome Version 29.0.1547.76

2- Safari Version 6.0.5 (7536.30.1)

*Ps I have no issue using Skype

please if anyone knows how to solve this reply to the post.

Best Regards,

Khaled