image responsive class 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: responsive svg with bootstrap
<svg version="1.1" viewBox="0 0 500 500">
<circle fill="#F7941E" stroke="#231F20" stroke-width="10"
cx="250" cy="250" r="200" opacity="0.6" />
</svg>