does anyone know how to get those pictures under the names of some people when they post?

You mean under your name at the left?

Sure. They are called 'Avatars' and need to be a specific size - "a width of 80 pixels, a height no greater than 80 pixels and a file size no more than 6kB"

You need to get the image you want and have it somewhere on the internet. Once there, click on your 'profile' button at the top of this page and type in the URL where the image is located.

Let me know if you don't have any webspace for yourself and I can host the image for you.

Mxx

thank you!