为什么我的OpenFileDialog不能在C#中显示图片？

using System;
using System.Windows.Forms;

namespace OpenFileDialogExample
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.Filter = "Image Files (*.jpg, *.png, *.bmp)|*.jpg;*.png;*.bmp";
            openFileDialog.ShowReadOnly = false;

            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                pictureBox1.Image = new System.Drawing.Bitmap(openFileDialog.OpenFile());
            }
        }
    }
}