Help please! strange Tkinter behavior has me totally baffled.

[Steve Ferg]

I have a short Python script that uses Tkinter to display an image.
Here is the script

===================================================================
import sys, os
from   Tkinter import *
root = Tk()      # A: create a global variable named "root"

def showPicture(imageFilename):
    # global root   #C: make root global
    root = Tk()  # B: create a local variable named "root"

    imageFrame = Frame(root)
    imageFrame.pack()

    imageObject = PhotoImage(file=imageFilename)

    label = Label(imageFrame,image=imageObject)
    label.pack()

    root.mainloop()

showPicture("python_and_check_logo.gif")
===================================================================

The strange thing is that it crashes with this traceback...

===================================================================

Traceback (most recent call last):
  File "easygui_test3.py", line 19, in <module>
showPicture("python_and_check_logo.gif")
  File "easygui_test3.py", line 14, in showPicture
label = Label(imageFrame,image=imageObject)
  File "L:\FergLabstatPublic\Python26\lib\lib-tk\Tkinter.py", line
2474, in __init__
Widget.__init__(self, master, 'label', cnf, kw)
  File "L:\FergLabstatPublic\Python26\lib\lib-tk\Tkinter.py", line
1940, in __init__
(widgetName, self._w) + extra + self._options(cnf))
_tkinter.TclError: image "pyimage1" doesn't exist

===================================================================

If I comment out either line A or line B, the script works fine.

What I don't understand is why creating a global "root" variable and a
local "root" variable causes the script to crash.

Even more puzzling... if I uncomment line C, so that "root" in line B
refers to a global "root" variable, the script still crashes.

I'm totally baffled.  Does anybody know what is going on here?

-- Steve Ferg
(I'm running Python 2.6 under Windows, but  I get the same behavior
under Solaris.)