从数据库sql server 读取图片A generic error occurred in GDI+.异常

从数据库sql server 读取图片A generic error occurred in GDI+.错误
private void button1_Click(object sender, EventArgs e)
  {
  SqlConnection conn = new SqlConnection(@"Data source=HERO;Integrated Security = SSPI;Initial Catalog = DevAndInnov");
  conn.Open();
  SqlCommand cmd = new SqlCommand("select im from test where xh='1a11'", conn);
  byte[] b = (byte[])cmd.ExecuteScalar();
  if (b.Length > 0)
  {
  MemoryStream stream = new MemoryStream(b, true);
  stream.Write(b, 0, b.Length);
  pictureBox1.Image = new Bitmap(stream);//该行出错*************
  stream.Close();

  }  
  }

请高手指教数据库im字段类型image

[解决办法]
你为什么还要
ms.Write(b, 0, b.Length); ?
直接
byte[] b = (byte[])cmd.ExecuteScalar(); 
if (b.Length > 0) 
{ 
MemoryStream stream = new MemoryStream(b, true); 
pictureBox1.Image = new Bitmap(stream);
stream.Close(); 

}

不就可以了
[解决办法]

C# code

SqlConnection conn = new SqlConnection("server=.;database=dbImate;uid=sa;pwd=;");            conn.Open();            SqlCommand cmd = new SqlCommand("select * from [image]", conn);            SqlDataReader dr = cmd.ExecuteReader();            dr.Read();            MemoryStream ms = new MemoryStream((Byte[])dr["pic"]);            Bitmap image = new Bitmap(ms);            image.Save(Server.MapPath("~/1.jpg"));            this.Image1.ImageUrl = "1.jpg";            dr.Close();            conn.Close();
[解决办法]
C# code
byte[] b = (byte[])cmd.ExecuteScalar();             if (b.Length > 0)             {                 MemoryStream stream = new MemoryStream(b, true);                 stream.Position = 0;//加上这句看看                pictureBox1.Image = new Bitmap(stream);                 stream.Close();             }