Images
Image Rounded & Circle
Use classes .rounded and .rounded-circle.
Image thumbnails
In addition to our border-radius utilities, you can use .img-thumbnail to give an image a rounded 1px border appearance.
Responsive images
Images in Bootstrap are made responsive with .img-fluid. max-width: 100%; and height: auto; are applied to the image so that it scales with the parent element.
Image Sizes
.avatar-sm
.avatar-md
.avatar-lg
.avatar-sm
.avatar-md
.avatar-lg
