Sorting pixels by various methods

pixelsort.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;

namespace PixelSort
{
    class Program
    {
        public static void Main(string[] args)
        {
            if (args.Length == 0)
            {
                Console.WriteLine("Please specify a filename");
                return;
            }

            var methods = new Dictionary<string, Func<Color[], Color[]>>(StringComparer.OrdinalIgnoreCase)
            {
                {"sum", (s) => s.OrderBy(c => c.R + c.G + c.B).ToArray()},
                {"hue", s => s.OrderBy(c => c.GetHue()).ToArray() },
                {"saturation", s => s.OrderBy(c => c.GetSaturation()).ToArray() },
                {"brightness", s => s.OrderBy(c => c.GetBrightness()).ToArray() },
                {"hash", s => s.OrderBy(c => c.GetHashCode()).ToArray() },
                {"r", s => s.OrderBy(c => c.R).ToArray() },
                {"g", s => s.OrderBy(c => c.G).ToArray() },
                {"b", s => s.OrderBy(c => c.B).ToArray() },
            };

            var method = methods["sum"];
            var vertical = false;
            var filename = args[0];

            if (args.Length >= 2 && methods.ContainsKey(args[1]))
            {
                method = methods[args[1]];
            }
            else if (args.Length >= 2)
            {
                Console.WriteLine("Unknown sorting method");
                return;
            }
            else
            {
                Console.WriteLine("Defaulting to sorting method: sum");
            }

            if (args.Any(a => a.Equals("vertical") || a.Equals("v")))
            {
                vertical = true;
            }

            using (var bmp = new Bitmap(filename))
            {
                var arr = new Color[bmp.Width];

                if (!vertical)
                {
                    for (var y = 0; y < bmp.Height; y++)
                    {
                        for (var x = 0; x < bmp.Width; x++)
                        {
                            arr[x] = bmp.GetPixel(x, y);
                        }

                        arr = method(arr);

                        for (var x = 0; x < bmp.Width; x++)
                        {
                            bmp.SetPixel(x, y, arr[x]);
                        }
                    }
                }
                else
                {
                    for (var x = 0; x < bmp.Width; x++)
                    {
                        for (var y = 0; y < bmp.Height; y++)
                        {
                            arr[y] = bmp.GetPixel(x, y);
                        }

                        arr = method(arr);

                        for (var y = 0; y < bmp.Height; y++)
                        {
                            bmp.SetPixel(x, y, arr[y]);
                        }
                    }
                }

                var info = new FileInfo(filename);
                var c = 1;
                while (true)
                {
                    filename = Path.Combine(info.DirectoryName, $"{info.Name} ({c}){info.Extension}");

                    if (File.Exists(filename))
                    {
                        c++;
                    }
                    else
                    {
                        break;
                    }
                }

                bmp.Save(filename);
            }
        }
    }
}