private void Worker_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker bw = (BackgroundWorker)sender;

            if (bw.CancellationPending)
            {
                e.Cancel = true;
                return;
            }

            api.GetPhotos();
        }
        private void UpdateFolder(object sender, EventArgs e)
        {
            UnsplashAPI api = UnsplashAPI.GetInstance();

            api.GetPhotos();
        }