<div class="container">
  <a href="#animals" class="item"><img src="https://placeimg.com/640/480/animals" alt="Animals"></a>
  <a href="#architecture" class="item"><img src="https://placeimg.com/640/480/architecture" alt="Architecture"></a>
  <a href="#nature" class="item"><img src="https://placeimg.com/640/480/nature" alt="Nature"></a>
  <a href="#people" class="item"><img src="https://placeimg.com/640/480/people" alt="People"></a>
  <a href="#tech" class="item"><img src="https://placeimg.com/640/480/tech" alt="Tech"></a>
</div>

.container {
  display: flex;
  margin-top: 50px;
}

.item {
  position: relative;
  display: block;
  flex: 1 1 0px;
}

.item img {
  display: block;
  max-width: 100%;
}