效果图

简单的定时器结合DoubleAnimation使用示例，实现轮播图淡化切入特效

代码部分

<Image x:Name="carouselImage" Margin="10" HorizontalAlignment="Center" VerticalAlignment="Center" Stretch="UniformToFill">
    <Image.Resources>
        <Storyboard x:Key="SwitchImageStoryboard">
            <DoubleAnimation Storyboard.TargetName="carouselImage" Storyboard.TargetProperty="Opacity" From="0" To="1" Duration="0:0:1" BeginTime="0:0:0" />
            <DoubleAnimation Storyboard.TargetName="carouselImage" Storyboard.TargetProperty="Opacity" From="1" To="0" Duration="0:0:1" BeginTime="0:0:3" />
        </Storyboard>
    </Image.Resources>
</Image>

 private void StartCarousel()
{
    timer = new DispatcherTimer();
    timer.Interval = new TimeSpan(0, 0, 4);
    timer.Tick += Timer_Tick;
    timer.Start();

    SetImageSource(currentImageIndex);
}

private void Timer_Tick(object sender, EventArgs e)
{
    currentImageIndex = (currentImageIndex + 1) % imageFiles.Count;
    SetImageSource(currentImageIndex);
}

private void SetImageSource(int index)
{
    var path = imageFiles[index];
    carouselImage.Source = GetImageCache(path);
    ((Storyboard)carouselImage.Resources["SwitchImageStoryboard"]).Begin();
}

private BitmapImage GetImageCache(string sUrl)
{
    BitmapImage bmp = null;
    BitmapImage img = new BitmapImage();
    img.BeginInit();
    img.CacheOption = BitmapCacheOption.OnLoad;
    img.UriSource = new Uri(sUrl);
    img.EndInit();
    img.Freeze();
    bmp = img;
    return bmp;
}