if(document.images) {
var imgs = new Array();
imgs[0] = new Image(); imgs[0].src = "img/m_home.gif"; 
imgs[1] = new Image(); imgs[1].src = "img/m_home2.gif"; 
imgs[2] = new Image(); imgs[2].src = "img/topics_other.gif"; 
imgs[3] = new Image(); imgs[3].src = "img/topics_other2.gif"; 
}
function paintBtn(id, imgname) {
if(document.images) {
if(imgs[imgname]) { document.images[id].src = imgs[imgname].src; }
else { document.images[id].src = imgname;}
}
}