Beginning January 9, app screenshots will be locked in iTunes Connect once your app has been approved. New screenshots may be uploaded when you submit a binary for an update to an existing app or a new app.
This small but important update shuts down a widely used scam tactic, where developers would upload game screenshots to get an app approved by Apple and then switch them out with screenshots from another popular app.
It also means delaying submitting the app binary until not only is my app done, but I’ve also finished the boring marketing stuff. Color me skeptical that it will stop scammers, but I’m sure that legitimate developers will be inconvenienced.