Alter background for Asus call screen

Hey guys, when you make a call with the Zenfone 2, the Asus "call screen" comes up. I seem to get a random slew of blurred ugly backgrounds. Is there any way to edit this, or choose which background it uses? There are quite a few ugly ones (in my opinion), and while it may not be that big of a deal, it's just something I'm curious about.

Thanks