How to set a picked image as background of a grid dynamically, save it in app local storage and retrieve it each time app is launched?
    BitmapImage BgBitmap = new BitmapImage();
    Image BgImg = new Image();
    private async void bgbtn_Click(object sender, RoutedEventArgs e)
    {
        var fop = new FileOpenPicker();
        fop.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
        fop.FileTypeFilter.Add(".jpg");
        fop.FileTypeFilter.Add(".png");
        fop.CommitButtonText = "OK";
        fop.ViewMode = PickerViewMode.Thumbnail;
        StorageFile file = await fop.PickSingleFileAsync();
        IRandomAccessStream stream= await file.OpenAsync(FileAccessMode.ReadWrite);
        await file.CopyAsync(ApplicationData.Current.LocalFolder, "BackgroundImg", NameCollisionOption.ReplaceExisting);
        await BgBitmap.SetSourceAsync(stream);
        BgImg.Source = BgBitmap;
    }
Now, how to set this BgImg as "mainGrid" Grid Background? and it will be nice if i can save the picked file in app storage and set tht file as background.
 
    