get ramdom image color in devexpress

Question

public Image GetRandomImage(int w, int h, Random r)
        {
           
            Color randomColor = DesignMode ? Color.Empty : GetRandomColor(r);
            Image img = new Bitmap(w, h);
            using (Graphics g = Graphics.FromImage(img))
                g.FillRectangle(new SolidBrush(randomColor), new Rectangle(0, 0, img.Width, img.Height));
            return img;
        }

        public Color GetRandomColor(Random r)
        {
            Thread.Sleep(3);
            return Color.FromArgb(r.Next(0, 255), r.Next(0, 255), r.Next(0, 255));
        }