Andrzej

<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<style>
.mySlides {display:none;}
</style>
<body>

<h1 class="w3-center">Manual Slideshow</h1>

<div class="w3-content w3-display-container">
  <img class="mySlides" src="img_snowtops.jpg" style="width:100%">
  <img class="mySlides" src="img_lights.jpg" style="width:100%">
  <img class="mySlides" src="img_mountains.jpg" style="width:100%">
  <img class="mySlides" src="img_forest.jpg" style="width:100%">
  <img src="https://upload.wikimedia.org/wikipedia/commons/d/d7/Leszno%2Culica_S%C5%82owia%C5%84ska.jpg"<img src=" height="400px" width="180px">
  <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/5/53/Ratusz_w_Lesznie_%282%29.jpg/1200px-Ratusz_w_Lesznie_%282%29.jpg"<img src=" height="400px" width="180px">
  <img src="https://s-ec.bstatic.com/images/hotel/max1024x768/957/95717615.jpg"<img src=" height="400px" width="180px">
  <img src="https://upload.wikimedia.org/wikipedia/commons/1/13/PL_Leszno_Rynek.JPG"<img src=" height="400px" width="180px">
  <img src="https://portalkomunalny.pl/wp-content/uploads/2017/06/wstazki-leszno-5.jpg"<img src=" height="400px" width="180px">
  <button class="w3-button w3-red w3-display-left" onclick="plusDivs(-1)">&#10094;</button>
  <button class="w3-button w3-red w3-display-right" onclick="plusDivs(1)">&#10095;</button>
</div>

<script>
var slideIndex = 1;
showDivs(slideIndex);

function plusDivs(n) {
  showDivs(slideIndex += n);
}

function showDivs(n) {
  var i;
  var x = document.getElementsByClassName("mySlides");
  if (n > x.length) {slideIndex = 1}
  if (n < 1) {slideIndex = x.length}
  for (i = 0; i < x.length; i++) {
    x[i].style.display = "none";
  }
  x[slideIndex-1].style.display = "block";
}
</script>

</body>