You can get everyone's Facebook profile picture using below.
You just call http://graph.facebook.com/USERNAME_OR_USERID/picture?type=large. This URL redirects you to image URL.
extention onto my answer:
how do I get the entire album?
You need https://graph.facebook.com/[uid]/albums?access_token=[AUTH_TOKEN] to get JSON array of all the albums of a user.
You will get three important things from here id - album id, name - album name, and type - album type.
What permissions do I need?
The permission required is user_photos see here
What is the best way to get ALL profile pictures from a given user?
Profile Pictures are under "Profile Pictures" album. To get to profile album, you need to look into albums array (as mentioned previously), iterate through the JSON result-set, until you get an album with name = Profile Pictures and type = profile. Get id of this object. This is the profile pictures album.
Now you can access it similar to you access any other album. That is, https://graph.facebook.com/[ALBUM_ID]/photos?access_token=[AUTH_TOKEN] this will list all the profile pictures of the user ever uploaded.
Hope this helps.
refer: http://developers.facebook.com/docs/reference/api/