[php] Facebook API - How do I get a Facebook user's profile image through the Facebook API (without requiring the user to "Allow" the application)

UPDATE:

Starting end August 2012, the API has been updated to allow you to retrieve user's profile pictures in varying sizes. Add the optional width and height fields as URL parameters:

https://graph.facebook.com/USER_ID/picture?width=WIDTH&height=HEIGHT

where WIDTH and HEIGHT are your requested dimension values.

This will return a profile picture with a minimum size of WIDTH x HEIGHT while trying to preserve the aspect ratio. For example,

https://graph.facebook.com/redbull/picture?width=140&height=110

returns

    {
      "data": {
        "url": "https://fbcdn-profile-a.akamaihd.net/hprofile-ak-ash4/c0.19.180.142/s148x148/2624_134501175351_4831452_a.jpg",
        "width": 148,
        "height": 117,
        "is_silhouette": false
      }
   }

END UPDATE

To get a user's profile picture, call

https://graph.facebook.com/USER_ID/picture

where USER_ID can be the user id number or the user name.

To get a user profile picture of a specific size, call

https://graph.facebook.com/USER_ID/picture?type=SIZE

where SIZE should be replaced with one of the words

square
small
normal
large

depending on the size you want.

This call will return a URL to a single image with its size based on your chosen type parameter.

For example:

https://graph.facebook.com/USER_ID/picture?type=small

returns a URL to a small version of the image.

The API only specifies the maximum size for profile images, not the actual size.

Square:

maximum width and height of 50 pixels.

Small

maximum width of 50 pixels and a maximum height of 150 pixels.

Normal

maximum width of 100 pixels and a maximum height of 300 pixels.

Large

maximum width of 200 pixels and a maximum height of 600 pixels.

If you call the default USER_ID/picture you get the square type.

CLARIFICATION

If you call (as per above example)

https://graph.facebook.com/redbull/picture?width=140&height=110

it will return a JSON response if you're using one of the Facebook SDKs request methods. Otherwise it will return the image itself. To always retrieve the JSON, add:

&redirect=false

like so:

https://graph.facebook.com/redbull/picture?width=140&height=110&redirect=false