public static class SplashScreenExtenstion
{
    public static void ShowSplashScreen(this Control control, SplashScreen splashScreen)
    {
        PictureBox pb = new PictureBox() { Size = control.Size };
        control.Controls.Add(pb);
        pb.BringToFront();
        int time = 0;
        pb.Paint += (o, e) => splashScreen.Draw(e.Graphics, control.ClientSize, time);
        System.Timers.Timer t = new System.Timers.Timer(1000);
        t.Elapsed += (o, e) =>
        {
            if (++time >= splashScreen.TotalTime)
            {
                t.Dispose();
                control.Invoke(new Action(() => control.Controls.Remove(pb)));
            }
            pb.Invoke(new Action(() => pb.Refresh()));
        };
        t.Start();
    }
}

public class SplashScreen
{
    private Color background;
    private Image image;
    private int t1, t2;

    public int TotalTime
    {
        get { return t1 + t2; }
    }

    public SplashScreen(Color background, int t1, Image image, int t2)
    {
        this.background = background;
        this.image = image;
        this.t1 = t1;
        this.t2 = t2;
    }

    public void Draw(Graphics g, Size size, int time)
    {
        if (time < t1)
            g.FillRectangle(new SolidBrush(background), 0, 0, size.Width, size.Height);
        else if (time >= t1 && time <= TotalTime)
            g.DrawImage(image, 0, 0, size.Width, size.Height);
    }
}