thumb1 = new Image();
thumb2 = new Image();
thumb3 = new Image();
thumb4 = new Image();
thumb5 = new Image();
thumb6 = new Image();


thumb1.src = "north_america/na_01_thumb.jpg";
thumb2.src = "north_america/na_02_thumb.jpg";
thumb3.src = "north_america/na_03_thumb.jpg";
thumb4.src = "africa/af_01_thumb.jpg";
thumb5.src = "africa/af_02_thumb.jpg";
thumb6.src = "africa/af_03_thumb.jpg";