readNifti(file, source = NULL, target = NULL, internal = FALSE)file contains a transformation,
these parameters can be used to specify the associated source and target
images, which are stored in attributes of the same name. Only used if
file is of unit length.FALSE (the default), an array
of class "niftiImage", containing the image pixel or voxel values,
will be returned. If TRUE, the return value will be an object of
class "internalImage", "niftiImage", and
possibly also "internalImage".writeNifti