using System;

using System.Linq;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

                ""data"": [

                    {

                        ""message"": ""Using Facebook's Graph Api to get Testdrive's news from the Facebook page on to the website. So this post will be visible in a minute at the website as well. Cool!"",

                        ""link"": ""https://www.facebook.com/TestdriveDressage/photos/a.493612667417831.1073741827.493607594085005/681741335271629/?type=1&relevant_count=1"",

                        ""picture"": ""https://scontent-b.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/s130x130/10394069_681741335271629_2094079936902591674_n.png?oh=85676b5ec301e78bd15e2cabde9b8f8f&oe=5561C419"",

                        ""id"": ""493607594085005_681741408604955"",

                        ""created_time"": ""2015-02-03T15:58:54+0000"",

                        ""attachments"": {

                            ""data"": [

                                {

                                    ""description"": ""Using Facebook's Graph Api to get Testdrive's news from the Facebook page on to the website. So this post will be visible in a minute at the website as well. Cool!"",

                                    ""media"": {

                                        ""image"": {

                                            ""height"": 666,

                                            ""src"": ""https://scontent-b.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/s720x720/10394069_681741335271629_2094079936902591674_n.png?oh=ac58799007b9b909ebc9f0ca762fd6c6&oe=554BD8A3"",

                                            ""width"": 720

                                        }

                                    },

                                    ""target"": {

                                        ""id"": ""681741335271629"",

                                        ""url"": ""https://www.facebook.com/TestdriveDressage/photos/a.493612667417831.1073741827.493607594085005/681741335271629/?type=1""

                                    },

                                    ""title"": ""Timeline Photos"",

                                    ""type"": ""photo"",

                                    ""url"": ""https://www.facebook.com/TestdriveDressage/photos/a.493612667417831.1073741827.493607594085005/681741335271629/?type=1""

                                }

                            ]

                        }

                    }

                ]

            }";

        JObject posts = JObject.Parse(json);

        JArray postItems = (JArray)posts["data"];

        foreach (JToken item in postItems.Where(item => item["message"] != null))

        {

            string url = (string)item.SelectToken("attachments.data[0].media.image.src");

            Console.WriteLine(url != null ? url : "(null)");

        }

    }

}

​