When I change an image of a button the button goes blank

Question

If I run the code below, the button I targeted with the change function just turns blank instead of switching to the image I need.

import tkinter
from PIL import Image,ImageTK

root = tkinter.Tk()
root.geometry("800x800")

canvas = tkinter.Canvas(width="800",height="800")
canvas.pack()

#and for example a button would be

b1 = {"button": tkinter.Button(canvas),"index":"lorem ipusm", "img": image}

def change(button,pic):
    photo = ImageTk.PhotoImage(pic)
    button["button"].configure(image = photo)
    button["img"] = pic

It only worked when I did this:

def change(button,pic):
    photo = ImageTk.PhotoImage(pic)
    button["button"].configure(image = photo)
    button["button"]()
    button["img"] = pic

I know that a button itself isn't callable, but with this it would word once, then throw an error that the button isn't callable.