Documentation and examples for opting images into responsive behavior(so they never become larger than their parent elements) and add lightweight styles to them—all via classes.
Responsive images
Images in Bootstrap are made responsive with .img-fluid. This applies max-width:100%;and height:auto;to the image so that it scales with the parent element.
<img src="..." class="img-fluid" alt="...">Image thumbnails
In addition to our border-radius utilities,you can use .img-thumbnailto give an image a rounded 1px border appearance.
<img src="..." class="img-thumbnail" alt="...">Aligning images
Align images with the helper float classes or text alignment classes. block-level images can be centered using the .mx-automargin utility class.
<img src="..." class="rounded float-start" alt="..."><img src="..." class="rounded float-end" alt="..."><img src="..." class="rounded mx-auto d-block" alt="..."><div class="text-center"><img src="..." class="rounded" alt="..."></div>