c# sql 插入图片

private void ShowImage(string sql)
  {
   //调用方法如：ShowImage("select Photo from UserPhoto where UserNo='" + userno +"'");
   SqlConnection conn=new SqlConnection ("server=(local);database=testphoto;uid=sa;pwd=");
   SqlCommand cmd = new SqlCommand(sql, conn);
   conn.Open();
   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);
        stream.Close();
       }
   conn.Close();
  }
  public void imgToDB(string sql)
  {   //参数sql中要求保存的imge变量名称为@images
   //调用方法如：imgToDB("update UserPhoto set Photo=@images where UserNo='" + temp + "'");
   SqlConnection con=new SqlConnection ("server=(local);database=testphoto;uid=sa;pwd=");

   FileStream fs = File.OpenRead(t_photo.Text);
   byte[] imageb = new byte[fs.Length];
   fs.Read(imageb, 0, imageb.Length);
   fs.Close();
   SqlCommand com3 = new SqlCommand (sql,con);
   com3.Parameters.Add("@images", SqlDbType.Image).Value = imageb;
   if (com3.Connection.State == ConnectionState.Closed)
    com3.Connection.Open();
   try
   {
    com3.ExecuteNonQuery();
   }
   catch
   {
    int a=1;
    a=1;
   }
   finally
   { com3.Connection.Close(); }
  }