void Button1Click(object sender, EventArgs e)
{
	//图片异步加载完成后的处理事件
	pictureBox1.LoadCompleted += new AsyncCompletedEventHandler(pictureBox1_LoadCompleted);
	//图片加载时，显示等待光标
	pictureBox1.UseWaitCursor = true;

	//采用异步加载方式
	pictureBox1.WaitOnLoad = false;

	//开始异步加载，图片的地址，请自行更换
	pictureBox1.LoadAsync("http://www.zu14.cn/wp-content/uploads/2009/02/image14.png");
}

void pictureBox1_LoadCompleted(object sender, AsyncCompletedEventArgs e)
{
	//图片加载完成后，将光标恢复
	pictureBox1.UseWaitCursor = false;
}