title: facebook api : getting user name/picture without prompting the user to login/authenticate right away
body: <p>Some sites these days (yelp??) show the users picture, name and ask the user to invite more friends or login using facebook. Only when the user clicks on login the user gets the window "xyz app is requesting following info, do you want to authenticate...."</p>
  
  <p>so how do they do that? basically get facebook user's name and picture without prompting him/her to login right away. I know you can use graph api and as long as u have the fb user id, u can access their public info: name picture etc. But how do you get fb uid at all without asking the user to authenticate/grant permissions right away?</p>
  
  <p>please shed some light on this.</p>
  
  <p>thanks!!</p>