如何使用通过文件对话框选择的文件？

Question

我的问题是如何使用我稍后会选择askopenfilename（）的文件，例如将它放在画布上？ 我该怎么做而不是＆＃34;？＆＃34; at＆＃34; Im =？＆＃34; ？ 谢谢 ！ 对不起，我是初学者

import tkinter as tk
from tkinter import *
from tkinter.filedialog import *



root=tk.Tk()
root.geometry('1000x690')
root.title("Baccalauréat ISN 2017")

# # #
def Open_Image():
askopenfilename()

# # #
B13= Button(root, text='Open Image', height=5, width= 25, command = askopenfilename)
B13.grid(row=1, column=5, sticky= W + E)

Im = ?
# # #




Nim = Im.resize((int((Im.width*514)/Im.height), 514))   #maxsize =(821, 514) ---> size of the canvas 821-length; 514 -height


nshow = ImageTk.PhotoImage(Nim)

Can = tk.Canvas(root, background = 'blue') 

Can.grid(row = 1, column = 0, rowspan = 6, columnspan = 5, sticky = W + E + N + S)
Cim = Can.create_image(0, 0,  anchor = NW, image = nshow) # "0, 0" space between the picture and the borders

# # #

mainloop()