private void exportBMP_Click(object sender, EventArgs e)
        {
            using (SaveFileDialog dlg = new SaveFileDialog())
            {
                dlg.Title  = "Save Dialog";
                dlg.Filter = "Bitmap Images (*.bmp)|*.bmp";
                if (dlg.ShowDialog(this) == DialogResult.OK)
                {
                    using (Bitmap bmp = new Bitmap(PB.Width, PB.Height))
                    {
                        PB.DrawToBitmap(bmp, new Rectangle(0, 0, bmp.Width, bmp.Height));
                        PB.Image = new Bitmap(PB.Width, PB.Height);

                        bmp.Save(dlg.FileName);
                        MessageBox.Show("Saved Successfully");
                    }
                }
            }
        }