How can I display an image in Python 3 using tkinter/ttk?

Question

The nub of the matter is, what am I doing wrong in the following code snippet?

    from tkinter import *
    from tkinter.ttk import *

    root = Tk()

    myButton = Button(root)
    myImage = PhotoImage(myButton, file='myPicture.gif')
    myButton.image = myImage
    myButton.configure(image=myImage)

    root.mainloop()

The error message I get from idle3 is as follows:

    >>> 
    Traceback (most recent call last):
      File "/home/bob/Documents/Python/tkImageTest.py", line 9, in <module>
        myButton.configure(image=myImage)
      File "/usr/lib/python3.2/tkinter/__init__.py", line 1196, in configure
        return self._configure('configure', cnf, kw)
      File "/usr/lib/python3.2/tkinter/__init__.py", line 1187, in _configure
        self.tk.call(_flatten((self._w, cmd)) + self._options(cnf))
    TypeError: __str__ returned non-string (type Button)
    >>> 

This error message has me stumped, I simply don't understand what it is trying to say. Any ideas?

I would also appreciate suggestions for changes...

Answer 1

The error seems to point to the myButton argument passed to PhotoImage. As you noted in your comment, PhotoImage was treating the widget object as a string (there are several options of type string; see a list of PhotoImage options here).

Your code will work if you implement that line without referencing the myButton object:

myImage = PhotoImage(file='myPicture.gif')

I'm not certain you need to alter the PhotoImage constructor. Look at the PhotoImage docs to determine the valid options (i.e. resource names) for that class. Quoting the help file:

Help on class PhotoImage in module tkinter:

class PhotoImage(Image)

| Widget which can display colored images in GIF, PPM/PGM format.
|    
|  Method resolution order:  
|      PhotoImage  
|      Image  
|      builtins.object  
|    
|  Methods defined here:
|    
|  __getitem__(self, key)  
|      # XXX config  
|    
|  __init__(self, name=None, cnf={}, master=None, **kw)  
|      Create an image with NAME.
|
|      Valid resource names: data, format, file, gamma, height, palette, 
|      width.

---

FYI: The easiest way to get to the docs from Python at the command line or from IDLE:

from tkinter import PhotoImage
help(PhotoImage)

And lastly, another useful link about this class is at http://tkinter.unpythonic.net/wiki/PhotoImage.