thumbnail bootstrap 4 code example

Example 1: bootstrap 4 center image

/* used mx-auto d-block */

<img class="mx-auto d-block" src="https://www.w3schools.com/bootstrap4/paris.jpg" alt="https://www.w3schools.com/bootstrap4/paris.jpg"/>

Example 2: bootstrap class align center image

class="mx-auto d-block"

Example 3: how to make image responsive bootstrap 4

<img src="..." class="img-fluid" alt="Responsive image">

Example 4: image responsive bootstrap 4

<img class="img-fluid" src="" alt=""> //This will make your image responsive

Example 5: 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">