thumbnail image size bootstrap 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 image size

.food1 img {
    width:100%;
    height: 230px;
}