<img class = " avatar 
              round 
              avatar-xs
            " 
        src = "img.jpg" 
        alt = "img"
  >

  <img class = " avatar 
              round 
              avatar-sm
            " 
        src = "img.jpg" 
        alt = "img"
  >

  <img class = " avatar 
              round 
              avatar-md
            " 
        src = "img.jpg" 
        alt = "img"
  >

  <img class = " avatar 
              round 
              avatar-lg
            " 
        src = "img.jpg" 
        alt = "img"
  >