Answers for "align image center boostrap 4"

bootstrap class align center image

class="mx-auto d-block"

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="...">