private void LeftRightToolStripMenuItem_Click(object sender, EventArgs e)
        {
            currentbmp = BitmapProcessing.RotateFlipRL(currentbmp);
            Image img = currentbmp;

            pictureBox1.Image = img;
        }
        private void GrayToolStripMenuItem_Click(object sender, EventArgs e)
        {
            currentbmp = BitmapProcessing.RGB2Gray(currentbmp);
            Image img = currentbmp;

            pictureBox1.Image = img;
        }