Dispatcher and Data Binding issue

Dear all,

I have the following code snipet

 _TagWorker.RunWorkerCompleted += (sender, e) =>
            {
                if (e.Result != null)
                {
                    Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
                    {
                        TagImage = e.Result as BitmapSource;
                        TagLoaded = true;    
                    }));
                }
                else
                {
                    //Display failed image
                }
            };

From that code, executed from a viemmodel, I am getting the e.result of a worker thread into a TagImage  which is an ImageSource.

The TagImage is directly bind to an Image source property in my WPF view. At the time the TagImage get updated I get an exception that says "Must create DependencySource on same Thread as the DependencyObject."

Why the error comes, I am executed the update in the application Dispatcher ?

Any idea how to solve ?

regards