var n=2;
var rnd=Math.floor(n*Math.random());
var img="";
if(rnd==0) {
  img="gfx/logo.jpg";
} else
if(rnd==1) {
  img="gfx/logo.gif";
};
document.write('<img width="290" height="80" border="0" src="'+img+'" alt="Dealer Home Page! - www.dealer.kom.pl">');