Edit in JSFiddle

$("[data-iswap]").on("click", function() {
  var $this = $(this);
  var $iSRC = $this.attr("src");
  var $newSRC = $this.data("iswap");
  var $oldSRC = $this.data("oswap");
  var $newImgSrc = $iSRC.replace(/\w+\.(?![com|net|org|biz|info|live|me|design])\w+/g, $newSRC);
  var $oldImgSrc = $iSRC.replace(/\w+\.(?![com|net|org|biz|info|live|me|design])\w+/g, $oldSRC);
  if ($newImgSrc.indexOf($iSRC) === -1) {
    $this.attr("src", $newImgSrc);
  } else {
    $this.attr("src", $oldImgSrc);
  }
});

<div class="container">
  <h2>Image Swap on Click</h2>
  <p>Click on the image to swap between the next image and then the original image.</p>
  <div class="d-flex justify-content-between align-items-start flex-wrap iswap">
    <img class="img-fluid" src="http://saj.bss.design/assets/img/desk.jpg?h=9943d0aaec924a3b7027809a369f32f6" data-iswap="building.jpg" data-oswap="desk.jpg">
    <img class="img-fluid" src="http://saj.bss.design/assets/img/building.jpg?h=caffb1c1581c5da2fb703dc76803cf86" data-iswap="loft.jpg" data-oswap="building.jpg">
    <img class="img-fluid" src="http://saj.bss.design/assets/img/loft.jpg?h=7089baf3aed19c1ebfdb3b22b910ec17" data-iswap="desk.jpg" data-oswap="loft.jpg">
  </div>
</div>

@media (min-width:768px) {
  .iswap img {
    max-width: 32%
  }
}