using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

         var imgObjDefinition = new[] { new[] { new { FileName = "", FileType = "", Length = "", Content = "", Type = "" } } };

                            var imageObject = JsonConvert.DeserializeAnonymousType("[[{\"FileName\": \"\", \"FileType\": \"\", \"Length\": \"\", \"Content\": \"\", \"Type\": \"\"}], [{\"FileName\": \"\", \"FileType\": \"\", \"Length\": \"\", \"Content\": \"\", \"Type\": \"\"}]]", imgObjDefinition);

        Console.Write(imageObject.Length);

        Console.Write(imageObject[0][0].Content);

    }

}