Add 10000 to numbers using Regex replace?

Photo.123.aspx

Photo.10123.aspx

Photo.12.aspx

Photo.10012.aspx

using System;
using System.Text.RegularExpressions;

namespace RenameAspxFile
{
    sealed class Program
    {
        private static readonly Regex _aspxFileNameRegex = new Regex(@"(S+.)(d+)(.aspx)", RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace | RegexOptions.IgnoreCase);
        private static readonly string[] _aspxFileNames= {"Photo.123.aspx", "Photo.456.aspx", "BigPhoto.789.aspx"};

        static void Main(string[] args)
        {
            Program program = new Program();
            program.Run();
        }

        void Run()
        {
            foreach (string aspxFileName in _aspxFileNames)
            {
                Console.WriteLine("Renamed '{0}' to '{1}'", aspxFileName, AddTenThousandToPhotoNumber(aspxFileName));
            }
        }

        string AddTenThousandToPhotoNumber(string aspxFileName)
        {
            return _aspxFileNameRegex.Replace(aspxFileName, match => String.Format("{0}{1}{2}", match.Result("$1"), Int32.Parse(match.Result("$2")) + 10000, match.Result("$3")));
        }
    }
}

s(
  Photo. (d{2,3}) .aspx
){
  "Photo." . ($1 + 10000) . ".aspx"
}xe

"Photo./d.aspx" and replace with "Photo.1000$1.aspx"
"Photo./d/d.aspx" and replace with "Photo.100$1.aspx"
"Photo./d/d/d.aspx" and replace with "Photo.10$1.aspx"

Regex          regex = new Regex(@"(ddd?)", RegexOptions.None);
        string result = regex.Replace(@"Photo.123.asp", delegate(Match m)
                                                {
                                                    return "Photo.1"
                                                        + m.Groups[1].Captures[0].Value.PadLeft(4, '0')
                                                        + ".aspx";
                                                }
        );

static public string Evaluator(Match match)
{
     return "Photo.1"
            + match.Groups[1].Captures[0].Value.PadLeft(4, '0')
            + ".aspx";
}

public void Code(params string[] args)
{
     string pattern = @"Photo.([d]+).aspx";
     string test = "Photo.123.aspx";
     Regex regex = new Regex(pattern);
     string converted = regex.Replace(test, Evaluator)
     Console.WriteLine(converted);
}

[^d][d]{2,3}[^d]

:s/Photo.d+.aspx/=Photo.submatch(0)+10000.aspx/g