file uploading

If your using FileUpload control then internally it will convert to bytes array and upload to server.

See bellow may help you it's i used for audio files.
// For storing uploaded file on server
 string virtualFolder = "~/Files/";
                string physicalFolder = Server.MapPath(virtualFolder);
                FileUpload1.SaveAs(physicalFolder + FileUpload1.FileName);
// Convert to byte array              
 Int32 intAudioSize = 0;
                Stream AudioStream = null;
                // Gets the Size of the File
                intAudioSize = FileUpload1.PostedFile.ContentLength;
                // Reads thefile
                AudioStream = FileUpload1.PostedFile.InputStream;
                byte[] AudioContent = new byte[intAudioSize + 1];
                int intStatus = 0;
                intStatus = AudioStream.Read(AudioContent, 0, intAudioSize);
              
              

                BinaryReader br = new BinaryReader(FileUpload1.PostedFile.InputStream);

                FileStream fstm = new FileStream(completeFileName, FileMode.Create, FileAccess.ReadWrite);
// writin file content on specified file
                BinaryWriter bw = new BinaryWriter(fstm);
// Byte array for database insertion if you want
                byte[] buffer = br.ReadBytes(FileUpload1.PostedFile.ContentLength);
                br.Close();

                bw.Write(AudioContent);
                bw.Flush();
                bw.Close();