As I understand it, the point of the "supermoon" is that it's closer to Earth in its orbit than it usually is, so appears larger relative to other things. Without context, the relative size is lost since you can always just look at it through a telescope/and or blow up the size of a picture of the moon.
In other words, unless there's other stuff in the frame of the photo to compare the relative size, it's indistinguishable from any other photo of a full moon.