System.Drawing.Bitmap.Save C# (CSharp) Method

        public void Save(string path)
        {
            if (path == null)
                throw new ArgumentNullException ("path");
            var format = ImageFormat.Png;

            var p = path.LastIndexOf (".");
            if (p != -1 && p < path.Length){
                switch (path.Substring (p + 1)){
                case "png": break;
                case "jpg": format = ImageFormat.Jpeg; break;
                case "tiff": format = ImageFormat.Tiff; break;
                case "bmp": format = ImageFormat.Bmp; break;
                }
            }
            Save (path, format);
        }

        private void RegisterCommands(ImagePresentationViewModel viewModel)
        {
            viewModel.SaveCommand = UICommand.Regular(() =>
            {
                var dialog = new SaveFileDialog
                {
                    Filter = "PNG Image|*.png|Bitmap Image|*.bmp",
                    InitialDirectory = Settings.Instance.DefaultPath
                };
                var dialogResult = dialog.ShowDialog();
                if (dialogResult.HasValue && dialogResult.Value)
                {
                    var tmp = viewModel.Image;
                    using (var bmp = new Bitmap(tmp))
                    {
                        if (File.Exists(dialog.FileName))
                        {
                            File.Delete(dialog.FileName);
                        }

                        switch (dialog.FilterIndex)
                        {
                            case 0:
                                bmp.Save(dialog.FileName, ImageFormat.Png);
                                break;
                            case 1:
                                bmp.Save(dialog.FileName, ImageFormat.Bmp);
                                break;
                        }
                    }
                }
            });
        }