Eu sou um estudante do mundo exterior, sem experiência anterior em programação. Eu tenho aprendido Python como uma extensão da minha aula de matemática. Eu tenho tentado criar um programa que gera fractais usando o Tkinter. O código funciona bem por si só, mas a inclusão de uma GUI de entrada do usuário causa um erro:

    Exception in Tkinter callback
    Traceback (most recent call last):
      File "C:\Python33\lib\tkinter\__init__.py", line 1475, in __call__
        return self.func(*args)
      File "C:\Python33\FractalGUI.py", line 74, in fractals
        canvas.create_image((0, 0), image = img, state = "normal", anchor = tkinter.NW)
      File "C:\Python33\lib\tkinter\__init__.py", line 2319, in create_image
        return self._create('image', args, kw)
      File "C:\Python33\lib\tkinter\__init__.py", line 2310, in _create
        *(args + self._options(cnf, kw))))
    _tkinter.TclError: image "pyimage1" doesn't exist

O código em si está abaixo. Observe que o erro não aparece até ocanvas.create_image linha é executada. Se houver outras informações que eu possa fornecer, entre em contato. Obrigado! :)

    import tkinter
    from tkinter import *

    #Creates widgets for user input
    class Imagespecs(Frame):

        def __init__(self,master):
            Frame.__init__(self,master)
             self.grid()
             self.y_axis()
             self.x_axis()

    #Y axis input
         def y_axis(self):
            self.instruction = Label(self,text = "How many pixels high do you want the image?")
            self.instruction.grid(row = 8, column = 0, columnspan = 2, sticky = N)

            self.height = Entry(self)
            self.height.grid(row = 10, column = 1, sticky = E)

    #Enters info to run fractal generation
            self.submit_button = Button(self,text = "Submit", command = self.fractals)
            self.submit_button.grid(row = 14, column = 2, sticky = E)

    #X axis input
         def x_axis(self):
             self.instruction2 = Label(self,text = "How many pixels wide do you want the image?")
             self.instruction2.grid(row = 4, column = 0, columnspan = 2, sticky = E)

            self.width = Entry(self)
            self.width.grid(row = 6, column = 1, sticky = E)

      #generates fractal
         def fractals(self):
             #Replace non-input
             content = self.width.get()
             content2 = self.height.get()

             if content == "":
                content = 500

             if content2 == "":
                content2 = 500

            #Create window specs
            WIDTH = int(content2); HEIGHT = int(content)
            xa = -2.0; xb = 1.0
            ya = -1.5; yb = 1.5
            maxIt = 256

             window = Tk()
             canvas = Canvas(window, width = WIDTH, height = HEIGHT, bg = "#000000")
             img = PhotoImage(width = WIDTH, height = HEIGHT)

             #The Newton-Raphson iteration
             h = HEIGHT
            for ky in range(HEIGHT):
                print (h)
                h = h - 1
                for kx in range(WIDTH):
                    c = complex(xa + (xb - xa) * kx / WIDTH, ya + (yb - ya) * ky / HEIGHT)
                    z = complex(0.0, 0.0)
                     for i in range(maxIt):
                        z = z * z + c
                        if abs(z) >= 2.0:
                            break
                     rd = hex(i % 4 * 64)[2:].zfill(2)
                     gr = hex(i % 8 * 32)[2:].zfill(2)
                     bl = hex(i % 16 * 16)[2:].zfill(2)
                     img.put("#" + rd + gr + bl, (kx, ky))

             canvas.create_image((0, 0), image = img, state = "normal", anchor = tkinter.NW)

             #Run GUI
             canvas.pack()
             mainloop()

     root = Tk()
     root.title("Fractal GUI")
     root.geometry("300x200")
     app = Imagespecs(root)

     root.mainloop()