C#中图片、二进制与字符串的相互转换方法

protected void Button1_Click(object sender, EventArgs e)
{
  //图片转二进制
  byte[] imageByte = GetPictureData(Server.MapPath("./uploadfile/111.png"));
  //二进制转换成字符串
  string picStr = Convert.ToBase64String(imageByte);
  //输出字符串
  Response.Write(picStr);
  //字符串转二进制
  byte[] imageBytes = Convert.FromBase64String(picStr);
  //读入MemoryStream对象
  MemoryStream memoryStream = new MemoryStream(imageBytes, 0, imageBytes.Length);
  memoryStream.Write(imageBytes, 0, imageBytes.Length);
  //二进制转成图片保存
  System.Drawing.Image image = System.Drawing.Image.FromStream(memoryStream);
  image.Save(Server.MapPath("./uploadfile/222.png"));
}
/// <summary>
/// 二进制流转图片
/// </summary>
/// <param name="streamByte">二进制流</param>
/// <returns>图片</returns>
public System.Drawing.Image ReturnPhoto(byte[] streamByte)
{
  System.IO.MemoryStream ms = new System.IO.MemoryStream(streamByte);
  System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
  return img;
}
/// <summary>
/// 图片转二进制
/// </summary>
/// <param name="imagepath">图片地址</param>
/// <returns>二进制</returns>
public byte[] GetPictureData(string imagepath)
{
  //根据图片文件的路径使用文件流打开，并保存为byte[]
  FileStream fs = new FileStream(imagepath, FileMode.Open);//可以是其他重载方法
  byte[] byData = new byte[fs.Length];
  fs.Read(byData, 0, byData.Length);
  fs.Close();
  return byData;
}
/// <summary>
/// 图片转二进制
/// </summary>
/// <param name="imgPhoto">图片对象</param>
/// <returns>二进制</returns>
public byte[] PhotoImageInsert(System.Drawing.Image imgPhoto)
{
  //将Image转换成流数据，并保存为byte[]
  MemoryStream mstream = new MemoryStream();
  imgPhoto.Save(mstream, System.Drawing.Imaging.ImageFormat.Bmp);
  byte[] byData = new Byte[mstream.Length];
  mstream.Position = 0;
  mstream.Read(byData, 0, byData.Length);
  mstream.Close();
  return byData;
}