How to convert BitmapImage to Byte Array - windows-phone-8

Question

I need to do the following:
Convert base64 image string into Bitmapimage
from BitmapImage in (1), convert it to byteArray
The problem:
how to solve the step(2)
Your help is greatly appreciated. Thanks
public async Task Base64StringToBitmap(string Base64source,string Filenm)
{
var bytes = Convert.FromBase64String(Base64source);
var ims = new InMemoryRandomAccessStream();
var dataWriter = new DataWriter(ims);
dataWriter.WriteBytes(bytes);
await dataWriter.StoreAsync();
ims.Seek(0);
//----- Create Bitmapimage ---------------
var bm = new BitmapImage();
bm.CreateOptions = BitmapCreateOptions.None;
bm.SetSource(ims);
// Update : added this
byte[] pixelBuffer = null;
using (MemoryStream ms = new MemoryStream())
{
WriteableBitmap wb = new WriteableBitmap(200, 300);
wb.SetSource(ims);
//-- Problem here :
Stream stm = wb.PixelBuffer.AsStream();
int len = (int)stm.Length;
byte[] pixels = new byte[len];
await stm.ReadAsync(pixels, 0, pixels.Length);
stm.CopyTo(ms);
pixelBuffer = ms.ToArray();
}
}

Answer 1

Check this method
public static byte[] ConvertToBytes(BitmapImage bitmapImage)
{
byte[] data = null;
using (MemoryStream ms = new MemoryStream())
{
WriteableBitmap btmMap = new WriteableBitmap
(bitmapImage.PixelWidth, bitmapImage.PixelHeight);
// write an image into the stream
Extensions.SaveJpeg(btmMap, ms,
bitmapImage.PixelWidth, bitmapImage.PixelHeight, 0, 100);
ms .Seek(0, SeekOrigin.Begin);
data = stream.GetBuffer();
}
return data;
}