Ask HN: What traffic should I expect from the App Store?

I'm launching an iOS app soon and I'm wondering what sort of traffic to expect from the App Store. This is over an app that lets users submit and download pictures. How much bandwidth should I expect to consume? How much CPU should be available? How much disk would be needed? How much of a peak should I expect in the beginning? Can anyone share some of these, hopefully including hard data? Thanks.