red and the format is auto-detected by
        `PIL.Image.open`.

    Returns
    -------
    `numpy.array`
        The image data. The returned array has shape

        - (M, N) for grayscale images.
        - (M, N, 3) for RGB images.
        - (M, N, 4) for RGBA images.

        PNG images are returned as float arrays (0-1).  All other formats are
        returned as int arrays, with a bit depth determined by the file's
        contents.
    r