I'm trying to get the profile pic of the user of the game using this-
void MyPictureCallback(FBResult result) // store user profile pic
{
        if (FB.IsLoggedIn)
        {
            WWW url = new WWW("http" + "://graph.facebook.com/" + FB.UserId + "/picture");
            Texture2D textFb2 = new Texture2D(128, 128, TextureFormat.ARGB32, false); //TextureFormat must be DXT5
            url.LoadImageIntoTexture(textFb2);
            profilePic.renderer.material.mainTexture = textFb2;
        }
But it isn't working. I am getting no errors.
Jason Pietka's answer is OK but a bit old.
Today we us FB.API:
FB.API("me/picture?type=med", Facebook.HttpMethod.GET, GetPicture);
GetPicture is a callback method so:
private void GetPicture(FBResult result)
{
    if (result.Error == null)
    {          
        Image img = UIFBProfilePic.GetComponent<Image>();
        img.sprite = Sprite.Create(result.Texture, new Rect(0,0, 128, 128), new Vector2());         
    }
}
I fixed it with this-
WWW url = new WWW("https" + "://graph.facebook.com/" + userId + "/picture?type=large"); //+ "?access_token=" + FB.AccessToken);
            Texture2D textFb2 = new Texture2D(128, 128, TextureFormat.DXT1, false); //TextureFormat must be DXT5
            yield return url;
            profilePic.renderer.material.mainTexture = textFb2;
            url.LoadImageIntoTexture(textFb2);
            Debug.Log("Working");
With Facebook SDK 7.2.2, this works fine if you want/need a square picture of particular size. Read more here on Facebook: https://developers.facebook.com/docs/graph-api/reference/user/picture/
public Image ProfilePicture;
FB.API("me/picture?type=square&height=128&width=128", HttpMethod.GET, FbGetPicture);
private void FbGetPicture(IGraphResult result)
{
    if (result.Texture != null)
        ProfilePicture.sprite = Sprite.Create(result.Texture, new Rect(0, 0, 128, 128), new Vector2());
}
Here is the tested code for Facebook SDK 7.10.1 to download profile picture
StartCoroutine(getFBPicture(AccessToken.CurrentAccessToken.UserId));
public IEnumerator getFBPicture(string facebookId)
    {
        var www = new WWW("http://graph.facebook.com/" + facebookId + "/picture?width=240&height=240&type=square&redirect=true");
        Debug.Log ("http://graph.facebook.com/" + facebookId + "/picture?width=210&height=210&type=normal&redirect=true"+"\t"+www.error);
        yield return www;
        if (www.isDone) {
            Debug.Log ("waiting" + www.bytesDownloaded);
            Texture2D tempPic = new Texture2D (25, 25);
            tempPic = www.texture;
            PlayerImage = tempPic;
        }
some how i was getting result.Texture was always null..
so i have used the code from https://github.com/fbsamples/friendsmash-unity
even this code have some problems if you compile directly..
LoadPictureAPI(Util.GetPictureURL("me", 100, 100),MyPictureCallback);
delegate void LoadPictureCallback (Texture texture);
IEnumerator LoadPictureEnumerator(string url, LoadPictureCallback callback)    
{
    WWW www = new WWW(url);
    yield return www;
    callback(www.texture);
}
void LoadPictureAPI (string url, LoadPictureCallback callback)
{
    FB.API(url,Facebook.HttpMethod.GET,result =>
           {
        if (result.Error != null)
        {
            Util.LogError(result.Error);
            return;
        }
        var imageUrl = Util.DeserializePictureURLString(result.Text);
        StartCoroutine(LoadPictureEnumerator(imageUrl,callback));
    });
}
void LoadPictureURL (string url, LoadPictureCallback callback)
{
    StartCoroutine(LoadPictureEnumerator(url,callback));
}
void MyPictureCallback(Texture texture)
{
    Util.Log("MyPictureCallback");
    Image im = GetComponent <Image>();
    if (texture ==  null)
    {
        LoadPictureAPI(Util.GetPictureURL("me", 100, 100),MyPictureCallback);
        return;
    }
    Vector2 v = new Vector2 (0, 0);
    Rect r = new Rect (0f,0f,100f,100f);
    im.sprite = Sprite.Create((Texture2D)texture, r, v);
}
来源:https://stackoverflow.com/questions/19756453/how-to-get-users-profile-picture-with-facebooks-unity-sdk