Images move to next line on smaller devices - html

Question

Expected behavior
Images should scale down/up and stay in the same line
Actual behavior
I created a row of images which should scale down on smaller devices, but they instead break into a new line.
I'm using Bootstrap 4.
Code
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<!-- src omitted -->
<div style="margin:auto; display:table;">
<img class="img-fluid" />
<img class="img-fluid" />
<img class="img-fluid" />
<img class="img-fluid" />
<img class="img-fluid" />
<img class="img-fluid" />
</div>
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>

Answer 1

Use flexbox and keep the default nowrap
.img-fluid {
min-width: 0;
}
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
<div class="d-flex justify-content-center">
<img class="img-fluid" src="https://picsum.photos/200/200?image=1069">
<img class="img-fluid" src="https://picsum.photos/200/200?image=1065">
<img class="img-fluid" src="https://picsum.photos/200/200?image=1063">
<img class="img-fluid" src="https://picsum.photos/200/200?image=1062">
<img class="img-fluid" src="https://picsum.photos/200/200?image=1063">
<img class="img-fluid" src="https://picsum.photos/200/200?image=1062">
</div>
And to scale on both direction you can add another container for the images:
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
<div class="d-flex justify-content-center">
<div><img class="img-fluid" src="https://picsum.photos/200/200?image=1069"></div>
<div><img class="img-fluid" src="https://picsum.photos/200/200?image=1065"></div>
<div><img class="img-fluid" src="https://picsum.photos/200/200?image=1063"></div>
<div><img class="img-fluid" src="https://picsum.photos/200/200?image=1062"></div>
<div><img class="img-fluid" src="https://picsum.photos/200/200?image=1063"></div>
<div><img class="img-fluid" src="https://picsum.photos/200/200?image=1062"></div>
</div>

Answer 2

You can use the built-in row and col class from bootstrap4 to achieve that.
Demo: http://jsfiddle.net/aq9Laaew/81140/
<div class="container">
<div class="row">
<div class="col">
<img class="img-fluid" />
</div>
...
</div>
</div>
You can also style them using flexbox.
Note: Make sure you use align-items: flex-start; or align-items: center; on the parent element, as align-items: stretch; is the default hence images will look horrible, like the accepted answer.
Updates:
The writer of the accepted answer said there is no difference when setting align-items: flex-start;. Here is the proof to show there is indeed: http://jsfiddle.net/aq9Laaew/81196/
The images without setting the align-items will default to stretch and they're stretched so much that I couldn't even capture them in the screenshot.
But yea the stretch effect might be what OP wants hence that's accepted answer.