private async void WriteableBitmapToStorageFile(WriteableBitmap bitmap, StorageFile file, FileFormat fileFormat)
{
Guid BitmapEncoderGuid = fileFormat.GetBitmapEncoder();
using (IRandomAccessStream stream = await file.OpenAsync(FileAccessMode.ReadWrite))
{
BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoderGuid, stream);
Stream pixelStream = bitmap.PixelBuffer.AsStream();
byte[] pixels = new byte[pixelStream.Length];
await pixelStream.ReadAsync(pixels, 0, pixels.Length);
encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore,
(uint)bitmap.PixelWidth,
(uint)bitmap.PixelHeight,
96.0,
96.0,
pixels);
await encoder.FlushAsync();
}
}