一个pictureBox控件，一个imagelist控件，两个Button

代码如下:

 private void Form1_Load(object sender, EventArgs e)
        {
            string Path = Application.StartupPath.Substring(0,Application.StartupPath.Substring(0,Application.StartupPath.LastIndexOf("\\")).LastIndexOf("\\"));
            Path += @"\11.jpg";
            string Path2 = Application.StartupPath.Substring(0, Application.StartupPath.Substring(0, Application.StartupPath.LastIndexOf("\\")).LastIndexOf("\\"));
            Path2 += @"\22.jpg";
            Image Ming = Image.FromFile(Path,true);
            imageList1.Images.Add(Ming);
            Image Ming2 = Image.FromFile(Path2, true);
            imageList1.Images.Add(Ming2);
            imageList1.ImageSize = new Size(200,165);
            pictureBox1.Width = 200;
            pictureBox1.Height = 165;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            pictureBox1.Image = imageList1.Images[0];
        }

        private void button2_Click(object sender, EventArgs e)
        {
            pictureBox1.Image = imageList1.Images[1];
        }

运行时，出现这个异常提示



这是ImageList控件的Image集合添加的两张图片


调试的情况如下：




请问各位前辈，为什么下标没有有效值？

因为你加入图片后改变了imagesize，导致你先加的图片用不了，先改变imagesize，再加入图片就可以了