void _asyncLoadFunction_ProgressChanged(object sender, PictureBoxLoadProgressChangedEventArgs e)
 {
     if (ProgressChanged != null)
     {
         ProgressChanged(this, e);
     }
 }
 static void pic_ProgressChanged(object sender, PictureBoxLoadProgressChangedEventArgs e)
 {
     Console.WriteLine("Progress Changed:{0} Length:{1}", e.ProgressPercentage, e.FileLength);
 }