iOS 7 - how to get full screen contacts?

[7earitup]

With iOS 7, when I call or receive a call, the contact photo of that person is in a small circle in the top right of my screen as opposed to being full screen like it used to be. I have tried to find information on how to switch from one method to the other but they don't seem to be consistent. Has anyone had any experience with this or is the small circle contact picture a permanent UI change now?

Thanks for any information!