public void WriteSomeImages()
        {
            using (var timeline = new DefaultTimeline())
            {
                timeline.AddVideoGroup(24, 320, 240).AddTrack(); // we want 320x240 sized images
                timeline.AddVideo("transitions.wmv");

                var participant = new ImagesToDiskParticipant(24, 320, 240, Environment.CurrentDirectory, 1, 2, 3, 4, 5,
                                                              6, 7);

                using (var render = new NullRenderer(timeline, null, new ICallbackParticipant[] {participant}))
                {
                    render.Render();
                }

                for (int i = 0; i < 6; i++)
                {
                    Assert.IsTrue(File.Exists(string.Format("frame{0}.jpg", i)));
                }
            }
        }