Reading a binay file (2 - GIF) Learn programming C#

using System;
using System.IO;
public class GifFile
{
    public static void Main()
    {
        byte[] data = new byte[5];
        BinaryReader file = new BinaryReader(File.Open("test.gif", FileMode.Open));

        for (int i = 0; i < 5; i++)
            data[i] = file.ReadByte();

        file.Close();

        if (data[0] == Convert.ToByte('G') &&
        data[1] == Convert.ToByte('I') &&
        data[2] == Convert.ToByte('F') &&
        data[3] == Convert.ToByte('8'))

            Console.WriteLine("Its a GIF8" + data[4]);
        else
            Console.WriteLine("It not gif file");
    }
}