Write image data to Netpbm file.

    Examples
    --------
    >>> image = numpy.array([[0, 1],[65534, 65535]], dtype=numpy.uint16)
    >>> imsave('_tmp.pgm', image)

def imsave(filename, data, maxval=None, pam=False):
    """Write image data to Netpbm file.

    Examples
    --------
    >>> image = numpy.array([[0, 1],[65534, 65535]], dtype=numpy.uint16)
    >>> imsave('_tmp.pgm', image)

    """
    try:
        netpbm = NetpbmFile(data, maxval=maxval)
        netpbm.write(filename, pam=pam)
    finally:
        netpbm.close()