Answers for "img bootstrap class"

responsive image in bootstrap

<img src="..." class="img-responsive">

image container bootstrap

<!-- FULL-WIDTH IMAGE --> 
<div class="container-fluid">
  <div class="row">
    <div class="col-12 px-0">
      <img class="img-fluid" src="your-image">
    </div>
  </div>  
</div>

<!-- 12 COLUMN IMAGE --> 
<div class="container-fluid">
  <div class="row">
    <div class="col-12">
      <img class="img-fluid" src="your-image">
    </div>
  </div>  
</div>

bootstrap img src

<img src="..." class="rounded mx-auto d-block" alt="...">

bootstrap Image thumbnails

In addition to our border-radius utilities, you can use 
.img-thumbnail to give an image a rounded 1px border appearance.

<img src="..." alt="..." class="img-thumbnail">