In my opinion, fine tuning the app metadata, including the screenshots should be possible to do at anytime, not just when you update the app. This annoying limitation no doubt saves work for Apple reviewers, but probably means a lot of store listings remain out of date since developers may not always have enough time to go through the whole process of updating the screenshots at the exact same time they roll out an app update.
TonyAU
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Last seen
User for
Post
Replies
Boosts
Views
Activity
This is useful, but only seems to be for reviews the developer has already responded to, not for new reviews.