Question: Is it possible to resize an image using tkinter only? If so, how can that be done?

Answer: 
You can resize a PhotoImage using the `zoom` and `subsample` methods. Both methods return a **new PhotoImage object**.

```
from tkinter import *
root = Tk()     #you must create an instance of Tk() first

image = PhotoImage(file='path/to/image.gif')
larger_image = image.zoom(2, 2)         #create a new image twice as large as the original
smaller_image = image.subsample(2, 2)   #create a new image half as large as the original

```

However, both of these methods can only take integer values as arguments, so the functionality is limited.

It is possible to scale by decimal values but it is slow and loses quality. The below code demonstrates scaling by 1.5x:

```
new_image = image.zoom(3, 3)            #this new image is 3x the original
new_image = new_image.subsample(2, 2)   #halve the size, it is now 1.5x the original

```
As far as I know (and it's been a while since I've touched Tkinter), it's a GUI toolkit. The closest it comes to "images" is the `PhotoImage` class which allows you to load them up and use them in your GUIs. If you want to edit/alter an image, I think you'd be better of using the [Python imaging library (PIL)](http://www.pythonware.com/products/pil/).