private void PictureBoxPoints_Paint(object sender, PaintEventArgs e)
{
    if (pictureBoxPoints.Image != null)
    {
        Bitmap bitmap = pictureBoxPoints.Image as Bitmap;
        double xFactor = (double)bitmap.Width / pictureBoxPoints.Width;
        double yFactor = (double)bitmap.Height / pictureBoxPoints.Height;
        double scaleFactor = Math.Max(xFactor, yFactor); // Ensure uniform scaling

        foreach (System.Drawing.Point point in _dotPoints)
        {
            int ellipseSize = (int)(5 / scaleFactor); // Ensure uniform scaling for the size
            int ellipseX = (int)(point.X / scaleFactor) - ellipseSize / 2;
            int ellipseY = (int)(point.Y / scaleFactor) - ellipseSize / 2;

            e.Graphics.FillEllipse(Brushes.Red, new Rectangle(ellipseX, ellipseY, ellipseSize, ellipseSize));
        }
    }
}