Image Resizer (console) [Final]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

// Credits to: csaki
// Exe download: https://hostr.co/eMXIFkX16sdR

namespace imageProcessor
{
    class Program
    {
        static string folder;
        static string[] filenames;
        static string path;
        static DateTime starttime;
        static DateTime endtime;
        static DateTime creationTime;
        static string filename;

        [STAThread()]
        static void Main()
        {
        Start:
            OpenFileDialog dialog = new OpenFileDialog();
            Console.Clear();
            Console.ForegroundColor = ConsoleColor.Yellow;
            Console.WriteLine("Welcome to my simple image resizer!");
            Console.WriteLine("Select all the .jpg/.png images you want to resize.");
            Console.WriteLine("(...and let the magic happen!)\n");
            Console.WriteLine("Currently jpg/png generating quality is set to 30 percent (optimal)");
            Console.WriteLine("Resized pictures are kept in a folder named \"Resized\".\n");
            Console.ForegroundColor = ConsoleColor.White;

            dialog.Multiselect = true;
            dialog.Title = "Select images";
            dialog.InitialDirectory = @"C:\";
            dialog.Filter = "Images (*.jpg, *.jpeg *.png) | *.JPG; *.jpg; *.JPEG; *.jpeg; *.PNG; *.png";
            if (dialog.ShowDialog() == DialogResult.OK)
            {
                starttime = DateTime.Now;
                folder = Path.GetDirectoryName(dialog.FileNames[0]);
                Log("Selected folder: " + folder);
                filenames = dialog.FileNames;
                Log("Got " + filenames.Length + " files!");
                Log("Starting image processing...");
                for (int i = 0; i < filenames.Length; i++)
                {
                    try
                    {
                        using (Bitmap img = new Bitmap(filenames[i]))
                        {
                            creationTime = File.GetCreationTime(filenames[i]);
                            filename = Path.GetFileName(filenames[i]);
                            FolderExists("Resized\\" + String.Format("{0:yyyy_MM}", creationTime));
                            path = Path.Combine(folder, "Resized", String.Format("{0:yyyy_MM}",
                                                                                              creationTime), filename);
                            SaveImage(path, img, 30);
                            Log("Resized: " + filename + " (" + (filenames.Length - i - 1) + " left)");
                        }
                    }
                    catch (Exception ex)
                    {
                        Console.ForegroundColor = ConsoleColor.Red;
                        Log("Ooops! Something happened!");
                        if (MessageBox.Show("Exception message:\n\n" + ex.Message + "\n\nDo you want to restart from the beginning?", "Error!", MessageBoxButtons.YesNo, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1) == DialogResult.Yes)
                        {
                            goto Start;
                        }
                        else Environment.Exit(-1);
                    }
                }
                Log("All of the images were successfully processed!");
            }
            else
            {
                if (MessageBox.Show("You haven't selected any files! Do you want to do so again?\n"
                    + "Press yes for restart, or no for exit.", "Error", MessageBoxButtons.YesNo, MessageBoxIcon.Exclamation, MessageBoxDefaultButton.Button1) == DialogResult.Yes)
                {
                    goto Start;
                }
                else Environment.Exit(0);
            }

            endtime = DateTime.Now;
            Log("Passed time: " + String.Format("{0} seconds\n", Math.Round((endtime - starttime).TotalSeconds, 2)));
            Log("Perhaps you want to resize more images? Y/N");
        Retry:
            ConsoleKeyInfo decision = Console.ReadKey();
            switch (decision.Key)
            {
                case ConsoleKey.Y:
                    goto Start;

                case ConsoleKey.N:
                    Environment.Exit(0);
                    break;
                default:
                    Log("Press Y or N!");
                    goto Retry;

            }
        }
        // Main ends

        //static void RenameFolders()
        //{
        //    string[] folders = Directory.GetDirectories(Path.Combine(folder, "Resized"));
        //    List<string> foldersForModify = new List<string>();
        //    for (int i = 0; i < folders.Length; i++)
        //    {
        //        if (folders[i].Substring(folders[i].LastIndexOf('\\') + 1).Contains(' '))
        //        {
        //            foldersForModify.Add(folders[i]);
        //        }
        //    }
        //    if (foldersForModify.Count == 0) return;

        //    string[] renamed = new string[foldersForModify.Count];
        //    string[] actualFoldernames = new string[renamed.Length];
        //    char[] chars = null;
        //    for (int i = 0; i < actualFoldernames.Length; i++)
        //    {
        //        actualFoldernames[i] = folders[i].Substring(folders[i].LastIndexOf('\\') + 1);
        //        chars = actualFoldernames[i].ToCharArray();
        //        for (int j = 0; j < chars.Length; j++)
        //        {
        //            if (chars[j] == ' ') chars[j] = '_';
        //        }
        //        actualFoldernames[i] = new string(chars);
        //        renamed[i] = folders[i].Substring(0, folders[i].LastIndexOf('\\') + 1) + actualFoldernames[i];
        //    }

        //    for (int i = 0; i < renamed.Length; i++)
        //    {
        //        if (folders[i] != renamed[i]) Directory.Move(folders[i], renamed[i]);
        //    }
        //}

        static void Log(string text)
        {
            Console.WriteLine("[{0:HH:MM:ss.ff}] {1}", DateTime.Now, text);
        }

        static void FolderExists(string f)
        {
            string path = Path.Combine(folder, f);
            if (Directory.Exists(path))
            {
                return;
            }
            else
            {
                Log("Creating path: " + path);
                Directory.CreateDirectory(path);
            }
        }

        static void SaveImage(string path, Image image, int quality)
        {
            if ((quality < 0) || (quality > 100))
                throw new ArgumentOutOfRangeException("Value must be between 0 and 100.");

            EncoderParameter qualityParam = new EncoderParameter(Encoder.Quality, quality);
            ImageCodecInfo imgCodec;
            if (path.Substring(path.LastIndexOf('.') + 1).ToLower() == "jpg" ||
                path.Substring(path.LastIndexOf('.') + 1).ToLower() == "jpeg")
                imgCodec = GetEncoderInfo("image/jpeg");
            else imgCodec = GetEncoderInfo("image/png");

            EncoderParameters encoderParams = new EncoderParameters(1);
            encoderParams.Param[0] = qualityParam;
            image.Save(path, imgCodec, encoderParams);
        }

        static ImageCodecInfo GetEncoderInfo(string mimeType)
        {
            string lookupKey = mimeType.ToLower();
            ImageCodecInfo foundCodec = null;
            if (Encoders.ContainsKey(lookupKey))
            {
                foundCodec = Encoders[lookupKey];
            }
            return foundCodec;
        }

        static Dictionary<string, ImageCodecInfo> encoders = null;

        static Dictionary<string, ImageCodecInfo> Encoders
        {
            get
            {
                if (encoders == null)
                {
                    encoders = new Dictionary<string, ImageCodecInfo>();
                }
                if (encoders.Count == 0)
                {
                    foreach (ImageCodecInfo codec in ImageCodecInfo.GetImageEncoders())
                    {
                        encoders.Add(codec.MimeType.ToLower(), codec);
                    }
                }
                return encoders;
            }
        }
    }
}