Hi,
Actually the tabs does not have to be saved separately, the options are saved on all tabs all of the time, regardless where the save is clicked. If you use any cache, make sure to clear it after saving, that would explain this issue.
Indeed, I can confirm there is a bug with the uploader. Strange this was not yet discovered yet. For now, I think you can bypass it by copy/pasting the image URL directly into the fields. I will make sure to fix this for the upcoming release.