public partial class MainWindow : Window, INotifyPropertyChanged
    {
        string path;
        public string Path { get { return path; } set { path = value; this.PropertyChanged(this, new PropertyChangedEventArgs("Path")); } }

        public event PropertyChangedEventHandler PropertyChanged;

        private ObservableCollection<string> imageList = new ObservableCollection<string>();
        public ObservableCollection<string> ImageList
        {
            get { return imageList; }
            set { imageList = value; PropertyChanged(this, new PropertyChangedEventArgs("ImageList")); }
        }

        public MainWindow()
        {
            InitializeComponent();

            ImageList = new ObservableCollection<string>();

            PropertyChanged += new PropertyChangedEventHandler(MainWindow_PropertyChanged);
            Path = Directory.GetCurrentDirectory() + @"\images";
        }

        void MainWindow_PropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            MethodInfo mi = this.GetType().GetMethod(e.PropertyName + "Changed");

            if (mi != null)
            {
                mi.Invoke(this, new object[] { });
            }
        }

        public void PathChanged()
        {
            string[] images = Directory.GetFiles(path, "*.jpg", SearchOption.AllDirectories);

            images.ToList().ForEach(x => ImageList.Add(x));
        }

        private void btnOpenDirectory_Click(object sender, RoutedEventArgs e)
        {
            FolderBrowserDialog dialog = new FolderBrowserDialog();

            if (dialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                Path = dialog.SelectedPath;
            }
        }
    }