title: get URI of image stored in isolatedstorage
body: <p>i have saved a file named 'logo.jpg' in the isolatedstorage using this code...</p>
  
  <pre><code>private void step2_Click(object sender, RoutedEventArgs e)
          {
              // Create a filename for JPEG file in isolated storage.
              String tempJPEG = "logo.jpg";
  
              // Create virtual store and file stream. Check for duplicate tempJPEG files.
              using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())
              {
                  if (myIsolatedStorage.FileExists(tempJPEG))
                  {
                      myIsolatedStorage.DeleteFile(tempJPEG);
                  }
  
                  IsolatedStorageFileStream fileStream = myIsolatedStorage.CreateFile(tempJPEG);
  
                  try
                  {
                      WriteableBitmap wb = new WriteableBitmap(img);
  
                      // Encode WriteableBitmap object to a JPEG stream.
                      Extensions.SaveJpeg(wb, fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85);
                  }
                  catch { }
                  //wb.SaveJpeg(fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85);
                  fileStream.Close();
              }
              NavigationService.Navigate(new Uri("/Stage2.xaml?num="+Contact_number.Text+"&amp;name="+contact_name.Text, UriKind.Relative));
          }
  </code></pre>
  
  <p>and creating tile using this function..</p>
  
  <pre><code>private StandardTileData GetSecondaryTileData()
      {
          string filePath = System.IO.Path.Combine(@"/Shared/ShellContent", "logo.jpg");
  
          StandardTileData tileData = new StandardTileData
          {
              Title = name,
              BackgroundImage = new Uri(@"isostore:" + filePath, UriKind.Absolute),
              Count = 0,
              BackTitle = "app",
              BackBackgroundImage = new Uri("", UriKind.Absolute),
              BackContent = "content"
          };
  </code></pre>
  
  <p>but it is throwing an exception 
  "An exception of type 'System.UriFormatException' occurred in System.ni.dll but was not handled in user code</p>
  
  <p>Additional information: Invalid URI: The URI is empty."</p>