<div id="container">
  <img class="floaty-left" src="https://placekitten.com/100/200">
  <img class="floaty-left" src="https://placekitten.com/100/100">
  <img class="floaty-left" src="https://placekitten.com/160/200">
  <img class="floaty-left" src="https://placekitten.com/100/120">
</div>

#container {
  max-width: 600px;
  margin: 0 auto;
  background-color: #eee;
  padding: 20px;
  background-color: #444;
}

.floaty-left {
  float: left;
  margin-right: 8px;
}
.floaty-right {
  float: right;
  margin-left: 8px;
}