MemoryStream ms = new MemoryStream(bytes); 
ms.Position = 0; 
Image img = Image.FromStream(ms); 
ms.Close(); 
this.pictureBox1.Image

System.Text.UnicodeEncoding converter = new System.Text.UnicodeEncoding(); 
byte[] inputBytes =converter.GetBytes(inputString); 
string inputString = converter.GetString(inputBytes);

string inputString = System.Convert.ToBase64String(inputBytes); 
byte[] inputBytes = System.Convert.FromBase64String(inputString); 
FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);

public byte[] StreamToBytes(Stream stream) 
{ 
  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); 
  return bytes; 
} 

public Stream BytesToStream(byte[] bytes) 
{ 
  Stream stream = new MemoryStream(bytes); 
  return stream; 
}

public void 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(); 
}

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; 
}

Bitmap BitReturn = new Bitmap(); 
byte[] bReturn = null; 
MemoryStream ms = new MemoryStream(); 
BitReturn.Save(ms, System.Drawing.Imaging.ImageFormat.Png); 
bReturn = ms.GetBuffer();