That would depend on how your want to do it... meaning if you want to take advantage of CSS3 and you don't mind that those browsers that don't fully support may see it differently or if you really need that all browsers see it exactly as it looks there.
Why am I saying this? because of the gradient. CSS3 can use gradientes but if you follow the CSS 2.1 route you'll need to use a background picture at the bottom.
Regarding the little triangle that points to the avatar, it is just a picture.