将图片文件转化成byte[]，从byte[]转化成string

1：将stream转化成byte[] public byte[] StreamToFile(Stream stream, string fileName)        {            // 把 Stream 转换成 byte[]             byte[] bytes = new byte[stream.Length];            stream.Read(bytes, 0, bytes.Length);            // 设置当前流的位置为流的开始             stream.Seek(0, SeekOrigin.Begin);            // 把 byte[] 写入文件             FileStream fs = new FileStream(fileName, FileMode.Create);            BinaryWriter bw = new BinaryWriter(fs);            bw.Write(bytes);            bw.Close();            fs.Close();            return bytes;        }2:将图片转化成stream        public Stream FileToStream(string fileName)        {            // 打开文件             FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);            // 读取文件的 byte[]             byte[] bytes = new byte[fileStream.Length];            fileStream.Read(bytes, 0, bytes.Length);            fileStream.Close();            // 把 byte[] 转换成 Stream             Stream stream = new MemoryStream(bytes);            return stream;        }3:将byte[]转化成stringpublic string GetStr(){             string path = System.Environment.CurrentDirectory + "\\caichi.jpg";                        string inputString = System.Convert.ToBase64String(StreamToFile(this.FileToStream(path),path));  byte[] bytes = System.Convert.FromBase64String(inputString);          MemoryStream ms = new MemoryStream(bytes);        ms.Position = 0;        Image img = Image.FromStream(ms);        ms.Close();        this.pictureBox1.Image = img;                       return inputString ;}