var img1 = new Image();
img1.src = 'gfx/navigation/navi_01-over.gif';
var img2 = new Image();
img2.src = 'gfx/navigation/navi_02-over.gif';
var img3 = new Image();
img3.src = 'gfx/navigation/navi_03-over.gif';
var img4 = new Image();
img4.src = 'gfx/navigation/navi_04-over.gif';
var img5 = new Image();
img5.src = 'gfx/navigation/navi_05-over.gif';
var img6 = new Image();
img6.src = 'gfx/navigation/navi_06-over.gif';