You should not insert the same image which you also use for featured image. You should use the featured image mainly. There is a Options Tab in NewsPress Options where you can configure something like you can set the first inserted image as featured image.
You configured the options so that the featured image is generated automatically from the first inserted image. You can control these from Appearance > NewsPress Options > Featured Image.
We request you to visit and read all options under NewsPress Options first.
