furas.pl
# prywatne notatki - Python, Linux, Machine Learning, etc.

Sometimes image can disappear when you move code into function. It is common problem with bug in PhotoImage with garbage collector which removes image from memory when image is assigned to local variable (variable created in function). You have to assign image to global variable or to some object - ie. to Label which displays this image.

Example which uses global

import tkinter as tk  # PEP8: `import *` is not preferred

def main(root):
    global img  # <-- solution for bug 

    img = tk.PhotoImage(file="image.png")
    label = tk.Label(image=img)
    label.pack()

if __name__ == "__main__":
    root = tk.Tk()
    main(root)
    root.mainloop()

Example which uses Label object

import tkinter as tk  # PEP8: `import *` is not preferred

def main(root):
    img = tk.PhotoImage(file="image.png")
    label = tk.Label(image=img)
    label.pack()

    label.img = img  # <-- solution for bug 

if __name__ == "__main__":
    root = tk.Tk()
    main(root)
    root.mainloop()

Not so long time ago you could find this information in popular documentation for tkinter on effbot.org but now this documentation disappeared.

I found old effbot.org in Wayback Machine from 2020.11.12: PhotoImage