new Thread(new ThreadStart(() => {
    var bitmap = new BitmapImage();
    bitmap.BeginInit();

    using (var stream = new MemoryStream(File.ReadAllBytes(...))) {
        bitmap.StreamSource = stream;
        bitmap.CacheOption = BitmapCacheOption.OnLoad;
        bitmap.EndInit();
        bitmap.Freeze();

    }
    this.Dispatcher.Invoke((Action)delegate {
        Image1.Source = bitmap;

    });

})).Start();

using (var stream = new FileStream(path, FileMode.Open)) {
    image.BeginInit();
    image.StreamSource = stream;

    image.DecodePixelWidth = 100;

    image.CacheOption = BitmapCacheOption.OnLoad;
    image.EndInit();
    image.Freeze();
}