var a1 = new Image();
var a2 = new Image();
var a3 = new Image();
var a4 = new Image();
var a5 = new Image();
var a6 = new Image();
var a7 = new Image();

a1.src = "popup_1.jpg";
a2.src = "popup_2.jpg";
a3.src = "popup_3.jpg";
a4.src = "popup_4.jpg";
a5.src = "popup_5.jpg";
a6.src = "popup_6.jpg";
a7.src = "popup_7.jpg";

function doButtons(picimage) {
document['picture'].src=picimage;
}