What is the trick between these?

[Peter Otten]

huey.y.jiang at gmail.com wrote:

> I am trapped by these two funny things:
> 
> class MyClass(upClass):
> 
>    def start(self):
>        ***do_menu_here****
> 
>        self.load_label_image()  # ---> this works
>        self.load_canvas_image()  # ---> this does not work
> 
>    def load_label_image(self):
>        img = PhotoImage(file="xx.gif")
>        Label(self, image=img).pack(side=BOTTOM, expand=YES, fill=BOTH)
>        return img
> 
>    def load_canvas_image(self):
>        img = PhotoImage(file="xx.gif")
>        self.canvas = Canvas(self, width=500, height=300, bg='white')
>        self.canvas.pack(expand=YES, fill=BOTH)
>        self.canvas.create_image(50, 0, image=img, anchor=NW)
> 
> if __name__ == '__main__':
>         root = Tk()
>         root.mainloop()
> 
> load_label_image() works. However, I cannot do BIND with it, because img
> has no method to do binding. So, I am trying load_canvas_image. Surprise,
> it does not work. These two defs are so similar, but Python complained
> that no attribute of load_canvas_image(). It is there, coexisting with
> load_label_image().
> 
> I cannot figure out what is wrong with it, can somebody tell me why?
> Thanks!

The only problem I see is that you do not keep a reference of the PhotoImage 
(as explained in MRAB's answer to your previous question).

What exception do you encounter? Do not paraphrase, copy and paste the 
actual traceback.