uploading image using c# desktop application

private void Button_changeImage_LinkClicked(object sender, ButtonClickedEventArgs e)
        {
            objLog.WriteLog("Came to Edit Image of Student on Admission Form");

            string imagename;
            FileDialog openFileDialog_scanImage = new OpenFileDialog();
            openFileDialog_scanImage.Filter = "Image File (*.jpg;*.bmp;)|*.jpg;*.bmp;";
            try
            {
                if (openFileDialog_scanImage.ShowDialog() == DialogResult.OK)
                {
                    imagename = openFileDialog_scanImage.FileName.ToString();
                    Bitmap newimg = new Bitmap(imagename);

                    image_student.SizeMode = PictureBoxSizeMode.StretchImage;

                    image_student.Image = (Image)newimg;

                }
                openFileDialog_scanImage = null;
            }
            catch (System.ArgumentException ae)
            {
              MessageBox.Show(ae.Message.ToString());

            }


        }