Windform c# pictureBox 更换背景图片

先初始化pictureBox的背景图片，想换背景图片，通过点击pictureBox控件区域换图片，再次打开程序背景图片是上次更换的图片
实现：
初始化pictureBox的背景图片的路径在工程下是固定的，点击pictureBox控件，使用OpenFileDialog类获取更换本地图片的路径，并更换背景图片，最后将获取到的图片通过流的方式写进初始化pictureBox的背景图片的路径。

初始化pictureBox背景图片

Image Img = Image.FromFile(Application.StartupPath + @"\Resources\Model.png");
Image bmp = new Bitmap(Img);
Img.Dispose();//FromFile()取图片会将图片锁定，无法进行写入操作，为了后面的操作，要将获取到的图片释放
pictureBox1.Image = bmp;
pictureBox1.SizeMode = PictureBoxSizeMode.CenterImage;

使用OpenFileDialog类获取更换本地图片的路径

private void pictureBox1_Click(object sender, EventArgs e){ 
	DialogResult DlgResult =  MessageBox.Show(@"Do you want to change the picture",@"Tip",
    MessageBoxButtons.OKCancel, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2);
    if (DlgResult != DialogResult.OK）{ 
    	return;
     }
     OpenFileDialog fileDialog = new OpenFileDialog();
     fileDialog.Multiselect = true;
     fileDialog.Title = "Please select file";
     fileDialog.Filter = "All Image Files(*.bmp;*.ico;*.gif;*.jpeg;*.jpg;*.png;*.tif;*.tiff)|*.bmp;*.ico;*.gif;*.jpeg;*.jpg;*.png;*.tif;*.tiff";
    if (fileDialog.ShowDialog() == DialogResult.OK){ 
    	localFilePath = fileDialog.FileName;//返回文件的完整路
        if (Image.FromFile(localFilePath).Height <= 234 || Image.FromFile(localFilePath).Width <= 300)
        { 
       		Image Img = Image.FromFile(localFilePath);
            Image bmp = new Bitmap(Img);
            Img.Dispose();
            pictureBox1.Image = bmp;
            pictureBox1.SizeMode = PictureBoxSizeMode.CenterImage;
            string strpath = Application.StartupPath + @"\Resources\Model.png";
            ZoomIn_control.CopyFile(localFilePath, strpath)；   
        }
        else
        { 
            MessageBox.Show(@"The picture is too large. Please select a new one", @"Warning");
         }
     }
 }

将获取到的图片通过流的方式写进初始化pictureBox的背景图片的路径

public static void CopyFile(string source, string target)
        { 
            using (FileStream fsRead = File.OpenRead(source))
            { 
                using (FileStream fsWrite = File.OpenWrite(target))
                { 
                    byte[] buffers = new byte[1024 * 4];

                    int length = fsRead.Read(buffers, 0, buffers.Length);
                    while (length > 0)
                    { 
                        Console.Write(". ");
                        fsWrite.Write(buffers, 0, length);
                        length = fsRead.Read(buffers, 0, buffers.Length);
                    }
                }
            }
        }