FlipTileTemplate.xaml.cs

public void RenderLiveTileImage(string filename, string title, string content)
{
    this.txtTitle.Text = title;
    this.txtContent.Text = content;

    this.Measure(new Size(336, 336));
    this.Arrange(new Rect(0, 0, 336, 336));
    this.UpdateLayout();

    WriteableBitmap image = new WriteableBitmap(336, 336);
    image.Render(this, null);
    image.Invalidate();

    using (IsolatedStorageFile output = IsolatedStorageFile.GetUserStoreForApplication())
    {
        using (var stream = output.OpenFile(filename, System.IO.FileMode.OpenOrCreate))
        {
            image.WritePNG(stream);
        }

        output.Dispose();
    }
}