bootstrap 4 small thumbnail code example
Example 1: bootstrap Aligning images
Align images with the helper float classes or text alignment classes.
block-level images can be centered using the .mx-auto margin utility class.
<img src="..." class="rounded float-left" alt="...">
<img src="..." class="rounded float-right" alt="...">
<img src="..." class="rounded mx-auto d-block" alt="...">
Example 2: responsive svg with bootstrap
.svg-container {
display: inline-block;
position: relative;
width: 100%;
padding-bottom: 100%;
vertical-align: middle;
overflow: hidden;
}