<div class="img-box">
  <img class="img" src="https://cdn.pixabay.com/photo/2022/07/10/19/28/mountains-7313638_960_720.jpg" alt="">
  <img class="img-hover" src="http://placekitten.com/800/500" alt="">
</div>
.img-box{
  position:relative;
  width: 400px;
  height: 400px;
}
.img-box img{
  position:absolute;
  width: 100%;
  height: 100%;
}
.img-box img.img-hover{
  display:none;
}
.img-box:hover img.img{
  display:none;
}
.img-box:hover img.img-hover{
  display:block
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.