I am getting an image from the CameraCaptureTask, and I would like to be able to make the image much smaller before saving. The width and height are automatically set to the highest resolution, which is much more than what I need. I have been trying to get the image, change the dimensions, and then attempt to save, although I am getting errors.

MainPage.xaml.cs

private void cameraTask_Completed(object sender,PhotoResult e)
    {
        if(e.TaskResult == TaskResult.OK)
        {
           
BitmapImage bmi = new BitmapImage();
           
bmi.SetSource(e.ChosenPhoto);
           
//MessageBox.Show(bmi.PixelWidth.ToString() + "x" +bmi.PixelHeight.ToString());
            var gcd= GCD(bmi.PixelWidth, bmi.PixelHeight);
            varresult = string.Format("{0}:{1}", bmi.PixelWidth / gcd,bmi.PixelHeight / gcd);
           
WriteableBitmap wb;            Stream stream;
            switch(result)
            {               
          case "3:4":                   
    wb = new WriteableBitmap(480,640);
                   
        break;
               
case "4:3":
                   
wb = new WriteableBitmap(640,480);
                   
break;
               
case "9:16":
                   
wb = new WriteableBitmap(448, 800);
                   
break;
               
case "16:9":
                   
wb = new WriteableBitmap(800, 448);
                   
break;
            }
            //Set the wb to the original stream?
           
wb.SetSource(e.ChosenPhoto); //ERROR saying Use of unassigned local variable 'wb'
           
//Convert the wb to a stream for saving  stream= new MemoryStream(wb.ToByteArray());
//Need to replace the following line with the new image stream for saving?
            //var capturedPicture = new CapturedPicture(e.OriginalFileName, e.ChosenPhoto);   
            var capturedPicture = new CapturedPicture(e.OriginalFileName, stream);          
        }
    }
    public int GCD(int a, int b)
    {
        while (a != 0 && b != 0)
        {      
            if (a > b)
                a %= b;
            else
                b %= a;
        }
        if (a == 0)
            return b;
        else
            return a;
    }