Memory leak in image control wpf

Question

I am working with Aforge.Net to get a single frame from webcam and display it through image control. whenever a user clicks the button i am trying to update the image control with a new image, fetched from the webcam . Everything seems to work fine but the memory usage keeps on going up. I don't no how to fix this issue in my app.

Bitmap _image = aforge.Test();
WebCamVideo.Source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
   _image.GetHbitmap()
  , IntPtr.Zero
  , System.Windows.Int32Rect.Empty
  , BitmapSizeOptions.FromWidthAndHeight(
        _image.Width
      , _image.Height)
);
WebCamVideo.Source.Freeze();
_image.Dispose();