Images
Images can be responsive to fit the parent's width, and also can be customized to be round shaped.
You can add the class img-responsive to
make your image fit the width of container. It's height will
get
adjusted by keeping the aspect ratio same. If you want to change the aspect ratio, you will have to
crop the image. You can add class img-round
to make your image round.
Examples
Responsive Image
<img class="img-responsive" src="https://picsum.photos/400/400" alt="random-img">
Round Image
<img class="img-responsive img-round" src="https://picsum.photos/400/400" alt="random-img">