var poczatek = 1;
var koniec = 62;
var teraz = 1;
var temp;

function change_val_down() {
  var b = document.getElementById('left_gal');
  b.src = "img/galeria/left-2.png";
  if(teraz !== poczatek) {
    teraz = teraz - 1;
    temp = "img/galeria/galeria (" + teraz + ").JPG";
    var a = document.getElementById('galeria_img');
    a.src = temp;
    a = document.getElementById('galeria_img_full');
    a.href = temp;
  } else {
    teraz = koniec;
    temp = "img/galeria/galeria (" + teraz + ").JPG";
    var a = document.getElementById('galeria_img');
    a.src = temp;
    a = document.getElementById('galeria_img_full');
    a.href = temp;
  }
}

function change_val_up() {
  var b = document.getElementById('right_gal');
  b.src = "img/galeria/right-2.png";
  if(teraz !== koniec) {
    teraz = teraz + 1;
    temp = "img/galeria/galeria (" + teraz + ").JPG";
    var a = document.getElementById('galeria_img');
    a.src = temp;
    a = document.getElementById('galeria_img_full');
    a.href = temp;
  } else {
    teraz = poczatek;
    temp = "img/galeria/galeria (" + teraz + ").JPG";
    var a = document.getElementById('galeria_img');
    a.src = temp;
    a = document.getElementById('galeria_img_full');
    a.href = temp;
  }
}