function winH() {
   if (window.innerHeight)
      /* NN4 a kompatibilni prohlizece */
      return window.innerHeight;
   else if
   (document.documentElement &&
   document.documentElement.clientHeight)
      /* MSIE6 v std. rezimu - Opera a Mozilla
      jiz uspely s window.innerHeight */
      return document.documentElement.clientHeight;
   else if
   (document.body && document.body.clientHeight)
      /* starsi MSIE + MSIE6 v quirk rezimu */
      return document.body.clientHeight;
   else
      return null;
}
function winW() {
   if (window.innerWidth)
      /* NN4 a kompatibilni prohlizece */
      return window.innerWidth;
   else if
   (document.documentElement &&
   document.documentElement.clientWidth)
      /* MSIE6 v std. rezimu - Opera a Mozilla
      jiz uspely s window.innerHeight */
      return document.documentElement.clientWidth;
   else if
   (document.body && document.body.clientWidth)
      /* starsi MSIE + MSIE6 v quirk rezimu */
      return document.body.clientWidth;
   else
      return null;
}
function resize_obrazku()
{
	var vyska_dokumentu = winH();
	var sirka_dokumentu = winW();
	var pomer = sirka/vyska;

	var nova_sirka = (sirka_dokumentu-40);
	var nova_vyska = nova_sirka/pomer;
	if(nova_vyska > (vyska_dokumentu-40))
	{
		nova_vyska = (vyska_dokumentu-40);
		nova_sirka= 	nova_vyska*pomer;
	}
	if(nova_vyska > 1024)
	{
		nova_vyska = 1024;
		nova_sirka= 	nova_vyska*pomer;
	}
	if(nova_sirka > 1280)
	{
		nova_sirka = 1280;
		nova_vyska= nova_sirka/pomer;
	}
	document.images[0].width = nova_sirka;
	document.images[0].height = nova_vyska;
}
document.onload = resize_obrazku();