using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

using System.IO;

using System.Linq;

​

​

public class Program

{

    public static void Main()

    {

        var list = FileSamples.SortNumerically();

        foreach (var item in list)

        {

            Console.WriteLine(item);

        }

    }

​

}

​

class FileSamples

{

    public static List<string> SortNumerically()

    {

        int? Sorter(string fileName) =>

            int.TryParse(Regex.Match(Path.GetFileName(fileName), @"\d+").Value, out var value) ? value : null;

​

        string[] names =

            [

                "C:\\DownLoads\\Path1\\image1.gif",

                "C:\\DownLoads\\Path1\\image11.gif",

                "C:\\DownLoads\\Path1\\image123.gif",

                "C:\\DownLoads\\Path1\\image342.gif",

                "C:\\DownLoads\\Path1\\image2.gif"

            ];

        string[] names2 =

            [

                "C:\\DownLoads\\Path2\\image12.gif",

                "C:\\DownLoads\\Path2\\image13.gif",

                "C:\\DownLoads\\Path2\\image129.gif",

                "C:\\DownLoads\\Path2\\image32.gif",

                "C:\\DownLoads\\Path2\\image14.gif"

            ];

​

        return names

            .Union(names2)

            .ToArray()

            .OrderBy(Sorter)

            .ToList();

    }

}       

​