var 
preload1=new Image();
preload1.src="images/tswd_on_04.gif";
preload2=new Image();
preload2.src="images/tswd_on_05.gif";
preload3=new Image();
preload3.src="images/tswd_on_06.gif";
preload4=new Image();
preload4.src="images/tswd_on_11.gif";
preload5=new Image();
preload5.src="images/tswd_on_12.gif";

function move_in(img_name,img_src) {
document[img_name].src=img_src;
}

function move_out(img_name,img_src) {
document[img_name].src=img_src;
}