GIFs Using Tkinter

[Jeff Epler]

gregor,
I was also able to get a reliable display using
        bytes = open(imgfile, "rb").read()
        bytes = base64.encodestring(bytes)
        img = PhotoImage(data=bytes)

If you're using Windows, the missing part may be the "b" (binary) option
when opening the file.  If not, you'll need to provide more information
about what you're doing.

Jeff