When I want to submit an app to the App Store for real (not just for beta testing), I will need a ton of screen captures.
This tutorial page (and possibly this doco page) might come in handy.
And they need to be a bunch of different sizes, and for a bunch of different locales.
The way to do that consistently and reliably (without going stark raving mad) is to use Fastlane.
I expect I’ll want to use Fastlane to: