root = tk.Tk()
root.image = tk.PhotoImage(file='startup.gif')
label = tk.Label(root, image=root.image, bg='white')
root.overrideredirect(True)
root.geometry('+250+250')
root.lift()
root.wm_attributes('-topmost', True)
root.wm_attributes('-disabled', True)
root.wm_attributes('-transparentcolor', 'white')
label.pack()
label.mainloop()
Transparent background in a Tkinter window