Function decode_into 

pub fn decode_into(
    data: &[u8],
    opts: LjpegOptions,
    dst: &mut [u16],
    dst_stride: usize,
    width: usize,
    height: usize,
) -> Result<LjpegHeader>

Decode a lossless JPEG stream whose rows map 1:1 onto width-sample image rows.