If horizontal viewpoint quantity information Nx and vertical viewpoint
quantity information Ny are predetermined quantities, a value of the
aspect ratio of the output image data to be finally output satisfies a
predetermined condition, and a 3D identification mark is contained in the
output image data, then an image recording device adds a first extension
as general-purpose 3D image data which can also be used in a conventional
device and records it. Accordingly, when 3D image data is output
(displayed and printed) in a conventional device, image data which can be
used as 3D image data (which can be viewed as a stereoscopic image) can
be output as general-purpose image data while image data which cannot be
used as 3D image data in the conventional device is not output as image
data. This prevents a confusion of general users.