public override IImageData GetThumbnail(ThumbnailDescriptor descriptor, Size size)
 {
     return _factory.CreateImage(descriptor.ReferenceImage, size);
 }
 public abstract IImageData GetThumbnail(ThumbnailDescriptor descriptor, Size size);
 public override bool TryGetThumbnail(ThumbnailDescriptor descriptor, Size size, out IImageData thumbnail)
 {
     thumbnail = null;
     return false;
 }
 public abstract bool TryGetThumbnail(ThumbnailDescriptor descriptor, Size size, out IImageData thumbnail);