Update picture c#

Question

Insert picture working fine, I have problem with update...some help?

 

string fileName;

 Upload image

 

private void buttonupload_Click(object sender, EventArgs e)
       {
           //Read image file
           using (OpenFileDialog ofd = new OpenFileDialog() { Filter = "JPEG|*.jpg|BMP|*.bmp|PNG|*.png|All Files|*.*", ValidateNames = true, Multiselect = false })
           {
               if (ofd.ShowDialog() == DialogResult.OK)
               {
                   fileName = ofd.FileName;

                   pictureBox1.Image = System.Drawing.Image.FromFile(fileName);
               }
           }
       }

 private void buttonsave_Click(object sender, EventArgs e)
        {

            byte[] img_arr = null;
            MemoryStream ms = new MemoryStream();
            pictureBox1.Image.Save(ms, pictureBox1.Image.RawFormat);
            img_arr = ms.GetBuffer();

 using (SqlConnection openCon = new SqlConnection(cs))
                {
                    string saveStaff = "INSERT INTO dbo.radnici ( data) VALUES (@data)";

                    using (SqlCommand querySaveStaff = new SqlCommand(saveStaff))
                    {
                     querySaveStaff.Connection = openCon;
                     querySaveStaff.Parameters.AddWithValue("@data", img_arr);


                            openCon.Open();
                        querySaveStaff.ExecuteNonQuery();
                        openCon.Close();

                    }
 }

 else
            {

                using (SqlConnection openCon = new SqlConnection(cs))
                {
                   string updateStaff = "UPDATE dbo.radnici SET data=@data  WHERE id= " + idTextBox.Text;

                    using (SqlCommand querySaveStaff = new SqlCommand(saveStaff))
                    {
                        queryupdateStaff.Connection = openCon;
                            queryupdateStaff.Parameters.AddWithValue("@data", img_arr);


                            openCon.Open();
                        queryupdateStaff.ExecuteNonQuery();
                        MessageBox.Show("Uspješno ste izmenili stavku!", "Informacija", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        openCon.Close();

                    }

                }

            }