图片保存到数据库的方法
http://topic.csdn.net/u/20081024/11/846e3e56-218b-4b07-b733-ee87dc2fe687.html?882064923

图片保存到数据库的方法：

  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 + "'");
  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
  { }
  finally
  { com3.Connection.Close(); }
  }  

数据库中读出图片并显示在picturebox中：

方法一：
private void ShowImage(string sql)
  {
  //调用方法如：ShowImage("select Photo from UserPhoto where UserNo='" + userno +"'");
  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();
  }

方法二：当在dg中选中某行时：
  private void dg_MouseUp(object sender, MouseEventArgs e)
  {
  //整行选择
  if (e.Button == System.Windows.Forms.MouseButtons.Left)
  {//用户编号，姓名，性别，身份证号，籍贯，学院，系所，校区，部门，电话，照片
  //显示相片
  object imgobj=dg[10, dg.CurrentRow.Index].Value;
  if (imgobj != null && !Convert.IsDBNull(imgobj))
  {
  byte[] imgb = (byte[])imgobj;
  MemoryStream memStream = new MemoryStream(imgb);
  try
  {
  Bitmap myimge = new Bitmap(memStream);
  this.pictureBox1.Image = myimge;
  }
  catch
  {
  DB.msgbox("从数据库读取相片失败！");
  }
  }
  else
  pictureBox1.Image = null;
  }
  }