JSFiddle - React, Tailwind, and code Playground

HTML

<div class="slideshow-container">
<div class="mySlides fade">
    <div class="numbertext">1 / 5</div>
    <img class="ImgThumbnail" src="http://srovnej.jednoduse.cz/img/svarec3.jpg" style="height:300px; width:100%;">
    <div class="text">Dělník</div>
  </div>

  <div class="mySlides fade">
    <div class="numbertext">2 / 5</div>
    <img class="ImgThumbnail" src="http://srovnej.jednoduse.cz/img/svarec.jpg" style="height:300px; width:100%;">
    <div class="text">Montér</div>
  </div>

  <div class="mySlides fade">
    <div class="numbertext">3 / 5</div>
    <img class="ImgThumbnail" src="http://srovnej.jednoduse.cz/img/svarec2.jpg" style="height:300px; width:100%;">
    <div class="text">Uklízečka</div>
  </div>
  <div class="mySlides fade">
    <div class="numbertext">4 / 5</div>
    <img class="ImgThumbnail" src="http://srovnej.jednoduse.cz/img/zamecnik.jpg" style="height:300px; width:100%;">
    <div class="text">kuchař</div>
  </div>
  <div class="mySlides fade">
    <div class="numbertext">5 / 5</div>
    <img class="ImgThumbnail" src="http://srovnej.jednoduse.cz/img/zamecnik2.jpg" style="height:300px; width:100%;">
    <div class="text">Striptérka</div>
  </div>

</div>

<br>

<!-- The dots/circles -->
<div style="text-align:center">
  <span class="dot" onclick="currentSlide(1)"></span>
  <span class="dot" onclick="currentSlide(2)"></span>
  <span class="dot" onclick="currentSlide(3)"></span>
  <span class="dot" onclick="currentSlide(4)"></span>
  <span class="dot" onclick="currentSlide(5)"></span>
</div>  

<div class="modal">
<span class="close">×</span>
<img class="modalImage" id="img01" style="max-height:800px; max-width:100%">
</div>

CSS

#myImg {
  border-radius: 5px;
  cursor: pointer;
  transition: 0.3s;
}

#myImg:hover {opacity: 0.7;}

/* The Modal (background) */
.modal {
  display: none; /* Hidden by default */
  position: fixed; /* Stay in place */
  z-index: 1; /* Sit on top */
  padding-top: 100px; /* Location of the box */
  left: 0;
  top: 0;
  width: 100%; /* Full width */
  height: 100%; /* Full height */
  overflow: auto; /* Enable scroll if needed */
  background-color: rgb(0,0,0); /* Fallback color */
  background-color: rgba(0,0,0,0.9); /* Black w/ opacity */
}

/* Modal Content (Image) */
.modal-content {
  margin: auto;
  display: block;
  width: 80%;
  max-width: 700px;
}


/* Add Animation - Zoom in the Modal */
.modal-content, #caption {
  animation-name: zoom;
  animation-duration: 0.6s;
}

@keyframes zoom {
  from {transform:scale(0)}
  to {transform:scale(1)}
}

/* The Close Button */
.close {
  position: absolute;
  top: 15px;
  right: 35px;
  color: #f1f1f1;
  font-size: 40px;
  font-weight: bold;
  transition: 0.3s;
}

.close:hover,
.close:focus {
  color: #bbb;
  text-decoration: none;
  cursor: pointer;
}

/* 100% Image Width on Smaller Screens */
@media only screen and (max-width: 700px){
  .modal-content {
    width: 100%;
  }
}

/* Slideshow container */
.slideshow-container {
display: block;
  max-width: 500px;
  height: 100%;
  display: flex;
    display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;  
  position: relative;
}

/* Hide the images by default */
.mySlides {
  display: none;
}

/* Next & previous buttons */
.prev, .next {
  cursor: pointer;
  position: absolute;
  top: 50%;
  width: auto;
  margin-top: -22px;
  padding: 16px;
  color: white;
  font-weight: bold;
  font-size: 18px;
  transition: 0.6s ease;
  border-radius: 0 3px 3px 0;
  user-select: none;
}

/* Position the "next button" to the right */
.next {
  right: 0;
  border-radius: 3px 0 0 3px;
}

/* On hover, add a black background color with a little bit see-through...

JavaScript

var slideIndex = 1;
showSlides(slideIndex);

// Next/previous controls
function plusSlides(n) {
  showSlides(slideIndex += n);
}

// Thumbnail image controls
function currentSlide(n) {
  showSlides(slideIndex = n);
}

function showSlides(n) {
  var i;
  var slides = document.getElementsByClassName("mySlides");
  var dots = document.getElementsByClassName("dot");
  if (n > slides.length) {slideIndex = 1}
  if (n < 1) {slideIndex = slides.length}
  for (i = 0; i < slides.length; i++) {
      slides[i].style.display = "none";
  }
  for (i = 0; i < dots.length; i++) {
      dots[i].className = dots[i].className.replace(" active", "");
  }
  slides[slideIndex-1].style.display = "block";
  dots[slideIndex-1].className += " active";
}


var modalEle = document.querySelector(".modal");
var modalImage = document.querySelector(".modalImage");
Array.from(document.querySelectorAll(".ImgThumbnail")).forEach(item => {
   item.addEventListener("click", event => {
      modalEle.style.display = "block";
      modalImage.src = event.target.src;
   });
});
document.querySelector(".close").addEventListener("click", () => {
   modalEle.style.display = "none";
});