function obrazek(src, sirka, vyska)
{
  sirka += 20;
  vyska += 20;
  s = ((sirka < screen.width) ? sirka : (screen.width - 40));
  v = ((vyska < screen.height) ? vyska : (screen.height - 60));

  volby = 'width=' + s + ',height=' + v +',resizable=yes';

  url = 'obrazek.php?o=' + escape(src.replace(/ /g, '+'));

  window.open(url, 'okno', volby);
}