[Tkinter] How do I change an image dynamically

[Barrowman]

I am trying to dynamically change a displayed picture to another picture on a GUI.
I have tried various suggested ways seen on websites and none have worked this far.
What am I doing wrong?

def TestLogic():
    stgImg = PhotoImage(file="Stage1.gif")
    label=ttk.Label(root, image=stgImg)
    label.image = stgImg
    return

Perhaps this little change might help

def TestLogic():
    stgImg = PhotoImage(file="Stage1.gif")
    label=ttk.Label(root, image=stgImg)
    label.image = stgImg
    root.update_idletasks()
    return