Regular Avatar would be a rectangular image. Use "avatar" class on your image, it will make it an avatar!

In cases where circular avatars would suit your UI more, use "avatar-circular" class with regular avatar class to make your avatar circular

To provide your needs for different avatar sizes, you can choose from "avatar-xl", "avatar-large", "avatar-medium" and "avatar-small". You can use these classes with all kind of avatars (regular, circular, text-avatars)

Text avatar would come in handy when there is no image available. You can use "avatar-circular" to make them circular. You can use it different size classes too.