仅在Win8下storyboard中的内存泄漏

我做了一个应用程序，其中有一个幻灯片。我在5台电脑上运行这个应用程序。3 Win7和2 Win8(都是x64，我的应用程序是x86)。在Win7-PC上我没有问题。在Win8下，我得到(在不可预测的时间之后)一些错误信息。outofmemory异常和UCEERR_RENDERTHREADFAILURE (HRESULT: 0x88980406)。微软是这样说的:

如果系统。报告outofmemoryexception，然后在性能监视器中监视进程的内存使用情况;特别是进程'虚拟字节，进程'私有字节和。net CLR内存#字节在所有堆计数器。还要在Windows任务管理器中监视该进程的用户对象和GDI对象。如果您可以确定某个特定的资源正在耗尽，那么就对应用程序进行故障排除，以修复导致资源消耗的任何原因。最终，这将解决System.OutOfMemoryException。

我不能只监视系统，等待错误发生1到5天。也许有人能看出我代码中的错误?

下面是我的xhtml代码:

    <Window.Resources>
    <Style x:Key="ImgZIndexStyle" TargetType="{x:Type Image}">
        <Setter Property="Panel.ZIndex" Value="2"/>
        <Style.Triggers>
            <Trigger Property="Image.Opacity" Value="1">
                <Setter Property="Panel.ZIndex" Value="3"/>
            </Trigger>
        </Style.Triggers>
    </Style>
    <Storyboard x:Key="FaderStoryboardHide1Show2">
        <DoubleAnimation Storyboard.TargetName="FirstImage" 
         Storyboard.TargetProperty="Opacity"
         To="0" Duration="0:00:01" />
        <DoubleAnimation Storyboard.TargetName="SecondImage" 
         Storyboard.TargetProperty="Opacity"
         To="1" Duration="0:00:01" />
    </Storyboard>
    <Storyboard x:Key="FaderStoryboardHide2Show1">
        <DoubleAnimation Storyboard.TargetName="SecondImage" 
         Storyboard.TargetProperty="Opacity"
         To="0" Duration="0:00:01" />
        <DoubleAnimation Storyboard.TargetName="FirstImage" 
         Storyboard.TargetProperty="Opacity"
         To="1" Duration="0:00:01" />
    </Storyboard>
</Window.Resources>
<Grid>
    <Grid Name="SlideShowGrid" ZIndex="0">
        <Button Name="SlideShowButton" Click="SlideShowButton_OnClick">
            <Grid>
                <Image x:Name="FirstImage" Stretch="UniformToFill" Style="{StaticResource ImgZIndexStyle}" Opacity="1" />
                <Image x:Name="SecondImage" Stretch="UniformToFill" Style="{StaticResource ImgZIndexStyle}" Opacity="0" />
            </Grid>
        </Button>
    </Grid>
</Grid>

And my Class:

private void SlideShowTimer_Tick(object sender, EventArgs e)
{
    Image newImage;
    Storyboard tempStoryboard;
    if (FirstImage.Opacity == 1)
    {
        tempStoryboard = (Storyboard)FindResource("FaderStoryboardHide1Show2");
        newImage = SecondImage;
    }
    else
    {
        tempStoryboard = (Storyboard)FindResource("FaderStoryboardHide2Show1");
        newImage = FirstImage;
    }
    if (_imageCounter >= _fileList.Count - 1)
        _imageCounter = 0;
    else
        _imageCounter++;
    newImage.Source = new BitmapImage(new Uri(_fileList[_imageCounter]));
    tempStoryboard.Begin();
}

if (newImage != null)
    newImage.Dispose();
newImage.Source = new BitmapImage(new Uri(_fileList[_imageCounter]));

Bitmap newImage;
....
mewImage.Dispose();