private void UpdateImage()
        {
            imgToShow = origImage.Copy();
            if (!sunDiskPositionAndSize.IsNull)
            {
                int thickness = 0; // fill out
                switch (currMouseActionRegime)
                {
                case MouseActionsRegime.Nothing:
                    thickness = 0;
                    break;

                case MouseActionsRegime.DrawingSunDisk:
                    thickness = 2;
                    break;

                case MouseActionsRegime.MovingSunDisk:
                    thickness = 2;
                    break;

                case MouseActionsRegime.ResizingSunDisk:
                    thickness = 2;
                    break;

                default:
                    break;
                }

                imgToShow.Draw(sunDiskPositionAndSize.CircleF(), new Bgr(Color.Orange), thickness);
            }

            ThreadSafeOperations.UpdatePictureBox(pbTheImage, imgToShow.Bitmap, true);
            ThreadSafeOperations.SetText(lblTitle, sunDiskPositionAndSize.ToString(), false);
        }