private void m_Controller_OnEnd(object sender, ThumbnailControllerEventArgs e)
 {
     // thread safe
     if (this.InvokeRequired)
     {
         this.Invoke(new ThumbnailControllerEventHandler(m_Controller_OnEnd), sender , e);
     }
     else
     {
         this.buttonCancel.Enabled = false;
         this.buttonBrowseFolder.Enabled = true;
     }
 }
 private void m_Controller_OnStart(object sender, ThumbnailControllerEventArgs e)
 {
 }
 private void m_Controller_OnAdd(object sender, ThumbnailControllerEventArgs e)
 {
     this.AddImage(e.ImageFilename);
     this.Invalidate();
 }