IOS 6: How do I add apps to the list in my privacy settings that requires access to my photos?

I am having a difficult time granting apps access to my photos. I often get messages like this:

"This app does not have access to your photos or videos. You can enable access in privacy settings"

The privacy settings on the other hand has a limited number of apps under photos - twitter, Instagram, Facebook, whatsapp and blogger.

How do I add other apps like viber, pic stitch and photo collage.