我需要帮助做一个tkinter程序，可变地打开一张图片

import tkinter as tk
from PIL import Image, ImageTk

window = tk.Tk()
window.title("图片查看器")

image_label = tk.Label(window)
image_label.pack()

def open_image():
    file_path = tk.filedialog.askopenfilename(filetypes=[("Image files", "*.jpg;*.jpeg;*.png")])
    if file_path:
        image = Image.open(file_path)
        image = image.resize((400, 400))  # 调整图片大小
        photo = ImageTk.PhotoImage(image)
        image_label.config(image=photo)
        image_label.image = photo  # 保持对图片对象的引用，防止被垃圾回收

open_button = tk.Button(window, text="打开图片", command=open_image)
open_button.pack()

window.mainloop()