For default avatar, You have to use inline attributes to set height and width of image. Use
class .avatar-{sm|lg|xl} to modify size of your avatar.
Wrap your content with .avatar class and wrap your text in .avatar-content to
create a avatar with initials. You can also use solid color initials.
Use class bg-{color-name} to change background color of your avatar.
Use class bg-light-{color-name} to change background color of your avatar.
Use .avatar-icon class for Icon variant
Use class .avatar-status-{online | offline | away | busy} after .avatar-content.
Wrap bunch of avatars with .avatar-group class.
Avatar info inside tooltip variant