background - outgoing call

If I select a photo in my photolibrary on my new IPhone 5 (iOs 6.0.1) for "both" (home- an lockscreen), the background changes and everything works fine. I see this background-pic. But then when I call my friends for which I doesn't have a profile pic in the contacts, the old pic is during the outgoing call in backgroundscreen. For an incoming call it works fine. Only when I select the background-pic especially for lockscreen, the backgroundscreen during an outgoing call changes to this background.