id = 1;

obr1 = new Image();
obr1.src = "pictures/prostor2.jpg";

obr2 = new Image();
obr2.src = "pictures/prostor3.jpg";
 
function Dalsi()
{
id++;
if (id <= 9)
{
document.images.obrazek.src = 'pictures/prostor'+id+'.jpg' ;
}
else
{
id = 1;
document.images.obrazek.src = 'pictures/prostor'+id+'.jpg' ;
}
}