sample.cs

var apng = new APNG("a.png");
if (apng.IsSimplePNG)
    PngImage.Source = BitmapFrame.Create(
        apng.DefaultImage.GetStream(), BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
else
    apng.ToAnimation().CreateStoryboardFor(PngImage).Begin(PngImage);