Tkinter resize background image to window size

This is example application that uses Pillow to resize image on the Label as the label changes size:

from tkinter import *

from PIL import Image, ImageTk

root = Tk()
root.title("Title")
root.geometry("600x600")
root.configure(background="black")



class Example(Frame):
    def __init__(self, master, *pargs):
        Frame.__init__(self, master, *pargs)



        self.image = Image.open("./resource/Background.gif")
        self.img_copy= self.image.copy()


        self.background_image = ImageTk.PhotoImage(self.image)

        self.background = Label(self, image=self.background_image)
        self.background.pack(fill=BOTH, expand=YES)
        self.background.bind('<Configure>', self._resize_image)

    def _resize_image(self,event):

        new_width = event.width
        new_height = event.height

        self.image = self.img_copy.resize((new_width, new_height))

        self.background_image = ImageTk.PhotoImage(self.image)
        self.background.configure(image =  self.background_image)



e = Example(root)
e.pack(fill=BOTH, expand=YES)


root.mainloop()

This is how it works using Lenna image as example:

Just sugesting a slight change in the answer. Using self.master.winfo_width(),self.master.winfo_height() instead of 'event' makes he adjustment to size much quicker.

import tkinter as tk
from PIL import Image, ImageTk
class Layout:
     def __init__(self,master):
       self.master = master
       self.rootgeometry()
       self.canvas = tk.Canvas(self.master)
       self.canvas.pack()
       self.background_image = Image.open('image_file.PNG') 
       self.image_copy = self.background_image.copy()
       self.background = ImageTk.PhotoImage(self.background_image)
       self.loadbackground()

    def loadbackground(self):
       self.label = tk.Label(self.canvas, image = self.background)
       self.label.bind('<Configure>',self.resizeimage)
       self.label.pack(fill='both', expand='yes')


   def rootgeometry(self):
       x=int(self.master.winfo_screenwidth()*0.7)
       y=int(self.master.winfo_screenheight()*0.7)
       z = str(x) +'x'+str(y)
       self.master.geometry(z)

  def resizeimage(self,event):
       image = self.image_copy.resize((self.master.winfo_width(),self.master.winfo_height()))
       self.image1 = ImageTk.PhotoImage(image)
       self.label.config(image = self.image1)

root = tk.Tk()
a = Styling.Layout(root)
root.mainloop()

I have modified the above code so it is not in a class

#!/usr/bin/python3.5

from tkinter import *
from tkinter import ttk
from PIL import Image, ImageTk

root = Tk()
root.title("Title")
root.geometry('600x600')

def resize_image(event):
    new_width = event.width
    new_height = event.height
    image = copy_of_image.resize((new_width, new_height))
    photo = ImageTk.PhotoImage(image)
    label.config(image = photo)
    label.image = photo #avoid garbage collection

image = Image.open('image.gif')
copy_of_image = image.copy()
photo = ImageTk.PhotoImage(image)
label = ttk.Label(root, image = photo)
label.bind('<Configure>', resize_image)
label.pack(fill=BOTH, expand = YES)

root.mainloop()