Image Upload as Byte data

Image Upload as Byte data 

if (FileUpload1.HasFile)
        {
            string filename = FileUpload1.PostedFile.FileName;

            string fileExtension = Path.GetExtension(FileUpload1.PostedFile.FileName);
            FileUpload1.PostedFile.SaveAs(Server.MapPath("~/Data/" + FileUpload1.FileName));
            ImageButton1.ImageUrl = "~/Data/" + FileUpload1.FileName;
            string file = FileUpload1.FileName;
            Response.Write("Uploaded" + file);

            using (Stream strm = FileUpload1.PostedFile.InputStream)
            {
                byte[] buffer = null;
                buffer = new byte[strm.Length];
                strm.Read(buffer, 0, (int)strm.Length);
            }
        }