public byte[] GetBinaryData(string path, int bufferSize)

    {

        MemoryStream ms = new MemoryStream();

        using (FileStream fs = File.Open(path, FileMode.Open, FileAccess.Read))

        {

            int bytesRead;

            byte[] buffer = new byte[bufferSize];

            while((bytesRead = fs.Read(buffer,0,bufferSize))>0)

            {

                ms.Write(buffer,0,bytesRead);

            }

        }

        return(ms.ToArray());

    }



    public void SaveBinaryData(string path, byte[] data, int bufferSize)

    {

        using (FileStream fs = File.Open(path, FileMode.Create, FileAccess.Write))

        {

            int totalBytesSaved = 0;

            while (totalBytesSaved<data.Length)

            {

                int remainingBytes = Math.Min(bufferSize, data.Length - totalBytesSaved);

                fs.Write(data, totalBytesSaved, remainingBytes);

                totalBytesSaved += remainingBytes;

            }

        }

    }

stackoverflow.com/questions/912985/modifying-xmp-data-with-c