I know how you get it of their full avatar, but I want the picture of their shoulders, (the ones on a profile on the left of their name, like this -> http://prntscr.com/jz1owf)
Thanks
You should be able to use the new headshot image for this from this page.
The ID for this is:
https://www.roblox.com/headshot-thumbnail/image?userId=48103520&width=420&height=420&format=png
where you replace the UserId with the player's after userId=
.