1. An image processing device comprising: circuitry configured to: set a flag to specify an image data from N viewpoints of image data, the image data used to display a 2D image; transform, when the flag specifies the image data to display the 2D image, the N viewpoints of image data into one piece of basic image data and N−1 pieces of additional image data by switching one viewpoint of the image data of the N viewpoints of image data with another viewpoint of the N viewpoints of image data; and transmit the one piece of basic image data the N−1 pieces of additional image data and the flag, wherein N is more than one, and the one piece of basic image data is image data used to display the 2D image.