ImageList 内存占用过高的问题，这个怎么解决一下？

代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace 相册片头自动生成器
{
public partial class Form1 : Form
{

    public static int i=0;
    public string[] picArr=null;
    public Form1()
    {
        CheckForIllegalCrossThreadCalls = false;
        InitializeComponent();
    }

    private void OPENfile_Click(object sender, EventArgs e)
    {
        ChooseFileDialog.ShowDialog();
    }

    private void ChooseFileDialog_FileOk(object sender, CancelEventArgs e)
    {
        i = 0;
        picArr = null;
        picArr = ChooseFileDialog.FileNames;
        listView1.Items.Clear();
        pic.Dispose();
        progressBar1.Maximum = picArr.Length;
        this.progressBar1.Value = 0;
        backgroundWorkerOpenfile.RunWorkerAsync();

    }
    private void backgroundWorkerOpenfile_DoWork(object sender, DoWorkEventArgs e)
    {
        openfile();
    }
    private void backgroundWorkerOpenfile_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        backgroundWorkerOpenfile.Dispose();
    }
    private void Form1_FormClosed(object sender, FormClosedEventArgs e)
    {
        Application.Exit();
    }
    private void backgroundWorkerOpenfile_ProgressChanged_1(object sender, ProgressChangedEventArgs e)
    {
        this.progressBar1.Value++;
    }
    private void openfile()
    {
        if (i < picArr.Length)
        {
            pic.Images.Add(Image.FromFile(picArr[i]));
            pic.ImageSize = new Size(144, 80);
            listView1.LargeImageList = pic;
            ListViewItem lvi = new ListViewItem();
            lvi.ImageIndex = i;
            this.listView1.Items.Add(picArr[i], i);
            this.progressBar1.Value++;
            GC.Collect();
        }
        else
        {
            return;
        }
        i++;
        openfile();
    }
}

}

如上图，打开了24张照片，1G内存就用完了~

采用代理模式，一次加载一张，仅供参考