I thought the same exact thing a couple of days ago. Then I uploaded it again in reverse order but instead it was random. They need to make a better UI for this. One where we dont even need to re-upload them, but arrows to move it up/down.
If you have new application screenshots for a version of your application, it is best to wait until this new version of your app is approved before updating your screenshots in iTunes Connect. Updating these before a version approval will change the screenshots for the currently-live application version. This best practice also applies to application metadata changes that you wish to coordinate for a specific version.
On the other hand, in the table in Appendix A it is stated that the screenshots are Locked, Version-level (page 153).
Version-level is:
If the item is marked on the Version, then the item information will relate to a specific version and may vary between versions.
Locked is:
If the item is marked as Locked, it can only be edited in an Editable State.
And a list of Editable states is:
Prepare For Upload, Waiting For Upload, Waiting For Review, Waiting For Export Compliance, Upload Received, Rejected, Developer Rejected, Invalid Binary, Missing Screenshot.
None of these states can be reached once the app is Ready For Sale by using any button in the iTunes Connect. The only reasonable thing that I can think of is submitting another minor version binary to Apple and looking for the possibility of changing the screenshots during the submission process.
The problem is (*):
If you have new application screenshots for a version of your application, it is best to wait until this new version of your app is approved before updating your screenshots in iTunes Connect.
Your app screenshots cannot be edited once your app has been approved. You can edit them in all other editable states.
Please note, when updating your app currently, you will be able to provide new screenshots and the new screenshots will not go live until the update is approved.
If you have any further questions regarding this, please let us know.
Images CAN be edited after an app is available for sale. This was changed at end of 2010. If you already have 5 images - the upload link will not work until you delete one. No need to worry - if you delete one and have any issues on the DPI or RGB of what you are trying to upload (get an error or it is rejected) you can always click 'cancel' rather than 'save' and your original images will remain.
I was able to change my screenshots after my app was ready for sale, just click on "View Details" in iTunes Connect, delete the old screenshots and replace them, then "Done". The change is not instant so wait a bit. Then you will see your new screenshots on AppStore ;)
Beginning January 9 [2013], 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.
There's been some back and forth on the possibility of changing screenshots of an app that is in "Ready for Sale" state, without having to upload new binary.
At one point it was possible, but as of January 9th 2013 it requires a new binary:
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. For
more information on capturing and using screenshots, read the Xcode
User Guide.
As of today, it appears you can't edit screenshots after you submit a new version. I tried everything but couldn't delete the draft screenshots until I finally removed my app from submission.
I usually use the time after submission to edit and improve the screenshots, but now have to be doing it before submission. This is a horrible change. Here is the email from support.
Being unable to now edit screenshots while an app is in "Waiting for
Review" status, is expected behavior.
Developer-facing documentation currently lists "Waiting for Review" as
a state where locked metadata can be edited. Screenshots should be the
only locked metadata that cannot be edited while an app is in the
"Waiting for Review" status.
We are currently updating the developer resources and documentation to
clarify