Universal App图片文件和图片byte[]信息转换为bitmap

//打开图片选择器，选择要发送的图片
var openPicker = new FileOpenPicker
{
　　ViewMode = PickerViewMode.Thumbnail,
   SuggestedStartLocation = PickerLocationId.PicturesLibrary
};
openPicker.FileTypeFilter.Add(".jpg");
openPicker.FileTypeFilter.Add(".jpeg");
var file = await openPicker.PickSingleFileAsync();

var path = "ms-appdata:///local/1.jpg";
var file = await StorageFile.GetFileFromApplicationUriAsync(new Uri(path));

//将图片文件读取为BitmapImage
var fileStream = await file.OpenReadAsync();
var bitmap = new BitmapImage();
await bitmap.SetSourceAsync(fileStream);

public async static Task<BitmapImage> ConvertBytesToBitmapImage(byte[] bytes)
{
        try
            {
                if (bytes == null || bytes.Length == 0) return null;

                var stream = new MemoryStream(bytes);
                var randomAccessStream = new InMemoryRandomAccessStream();
                using (var outputStream = randomAccessStream.GetOutputStreamAt(0))
                {
                    var dw = new DataWriter(outputStream);
                    var task = new Task(() => dw.WriteBytes(stream.ToArray()));
                    task.Start();
                    await task;
                    await dw.StoreAsync();
                    await outputStream.FlushAsync();

                    var bitmapImage = new BitmapImage();
                    await bitmapImage.SetSourceAsync(iRandomAccessStream);
                    return bitmapImage;
                }
            }
            catch (Exception exception)
            {
                Debug.WriteLine("[Error] Convert bytes to BitmapImage failed,exception:{0}", exception);
                return null;
            }
}