Answers for "how to align image center in bootstrap 4"

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"/>

bootstrap class align center image

class="mx-auto d-block"

image responsive bootstrap 4

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