How to zoom out of image with tkinter?

I am making a tkinter script in Python 3 that displays a GIF image. Everything is working but the image is too zoomed in. How do I zoom out? Here is the code so far:

import time
from tkinter import *
global tk
tk = Tk()
tk.title("No Drugs PSA Smoking Picture")
global canvas
canvas = Canvas(tk, width=9000, height=9000)
canvas.pack()
slideone = PhotoImage(file='c:\\slide1nspsa.gif')
canvas.create_image(0, 0, anchor=NW, image=slideone)

Hopefully someone can answer... Also, please don't just comment on this question, please answer...