如何用C#编程序实现利用pictureBox控件循环打开若干张图片文件

设计：
namespace winform_csharp
{
partial class Form1
{
///

/// Required designer variable.
///

private System.ComponentModel.IContainer components = null;

///

/// Clean up any resources being used.
///

/// true if managed resources should be disposed; otherwise, false.
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}

#region Windows Form Designer generated code

///

/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
///

private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
this.pictureBox1 = new System.Windows.Forms.PictureBox();
this.timer1 = new System.Windows.Forms.Timer(this.components);
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
this.SuspendLayout();
//
// pictureBox1
//
this.pictureBox1.Location = new System.Drawing.Point(39, 28);
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.Size = new System.Drawing.Size(403, 214);
this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.Zoom;
this.pictureBox1.TabIndex = 0;
this.pictureBox1.TabStop = false;
//
// timer1
//
this.timer1.Enabled = true;
this.timer1.Interval = 1000;
this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(498, 266);
this.Controls.Add(this.pictureBox1);
this.Name = "Form1";
this.Text = "Form1";
this.Load += new System.EventHandler(this.Form1_Load);
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
this.ResumeLayout(false);

}

#endregion

private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.Timer timer1;
}
}
资源文件：
添加一个资源文件Resource1.resx
往里面添加4张图片，图片名称分别设置为：
Blue_hills, Sunset, Water_lilies, Winter
代码：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace winform_csharp
{
public partial class Form1 : Form
{
Bitmap[] map = { Resource1.Blue_hills, Resource1.Sunset, Resource1.Water_lilies, Resource1.Winter};
int i = 0;
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{

}

private void timer1_Tick(object sender, EventArgs e)
{
if (i == 4)
i = 0;
pictureBox1.Image = map[i];
i++;
}
}
}