using System;

using Newtonsoft.Json;

public class Program

{

    private static string JsonWithNull = @"{ 'height': '25', 'width': null }";

    public static void Main()

    {

        var settings = new JsonSerializerSettings()

        {

            NullValueHandling = NullValueHandling.Ignore

        };

        Image image = JsonConvert.DeserializeObject<Image>(JsonWithNull, settings);

        Console.WriteLine("The image has a height of '{0}' and a width of '{1}'", image.height, image.width);

    }

}

​

public class Image

{   

    public int height { get; set; }

    public Uri url { get; set; }

    public int width { get; set; }

}