Giving this converter that converts bytes[] to a BitmapImage()

    public class ByteArrayToImageConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, string language)
        {
            if (!(value is byte[] bytes))
                return null;

            var image = new BitmapImage();

#if WINDOWS_UWP
            using (var stream = new InMemoryRandomAccessStream())
            {
              image.SetSource(stream);
              var s = stream.AsStreamForWrite();
              s.Write(bytes, 0, bytes.Length);
            }
#else
            using (Stream stream = new MemoryStream(bytes))
            {
                image.SetSource(stream);
            }
#endif
            return image;
        }

        public object ConvertBack(object value, Type targetType, object parameter, string language)
        {
            throw new NotImplementedException();
        }
    }

The WINDOWS_UWP part and the part for other platforms is symmetric. However, when trying in, for instance, Android, this code produces the following exception:

System.ObjectDisposedException: : 'Can not access a closed Stream.'

As a workaround, the converter should be written as:

    public class ByteArrayToImageConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, string language)
        {
            if (!(value is byte[] bytes))
                return null;

            var image = new BitmapImage();

#if WINDOWS_UWP
            using (var stream = new InMemoryRandomAccessStream())
            {
              image.SetSource(stream);
              var s = stream.AsStreamForWrite();
              s.Write(bytes, 0, bytes.Length);
            }
#else
            Stream stream = new MemoryStream(bytes);
            image.SetSource(stream);
#endif
            return image;
        }

        public object ConvertBack(object value, Type targetType, object parameter, string language)
        {
            throw new NotImplementedException();
        }
    }

Please, notice that the #else part no longer encloses the stream in a using block, so the stream isn't disposed.

I don't know what are the implications of this, but I would like to point out that the stream should be disposed eventually. We need to ensure that the resources are freed properly.

I would like to put into consideration that this converter raises the concert of SetSource not behaving the same between platforms, not only in the abstractions used, but also regarding the life cycle of the underlying stream.

I personally think this should be improved.