private void tweetBtnClicked(object sender, RoutedEventArgs e)
{
// the bitmap image that need to post
BitmapSource bitmap = _selectedImg.Source as BitmapSource;
// the text that need to post
String newTweet = _tweetTxt.Text;
// do the tweet post
Twitter twitter = new Twitter(this);
_tweetBtn.Content = "Uploading...";
twitter.postTweet(newTweet, bitmap, this);
ResetTimer();
}