var sirka = screen.width-70;
    var vyska = screen.height-70;

    function fVyska() {
     var vvyska = document.getElementById('photo').offsetHeight+80;
     if (vyska>vvyska)
     {
       return vvyska;
     }  
     else
     {
       return vyska;
     }  
    }
    function fSirka() {
     var vsirka = document.getElementById('galerie-img').offsetWidth+80;
     if (sirka>vsirka)
     {
       return vsirka;
     }  
     else
     {
       return sirka;
     }
    }
    function pVyska() {
      var vv = fVyska();
      return (screen.height-fVyska())/2;
    }
    function pSirka() {
      var vv = fSirka();
      return (screen.width-fSirka())/2;
    }