function img1(nr) {
	img=new Image();
    img.src = 'i/'+nr+'.gif';
	document.images[nr].src=img.src;
}

function img2(nr) {
	img=new Image();
    img.src = 'i/'+nr+'_a.gif';
	document.images[nr].src=img.src;
}

function img3(nr) {
	img=new Image();
    img.src = 'i/'+nr+'.png';
	document.images[nr].src=img.src;
}

function img4(nr) {
	img=new Image();
    img.src = 'i/'+nr+'_a.png';
	document.images[nr].src=img.src;
}