Can't draw to canvas in Tkinter after() loop

I'm having a problem, when I try to create an image on the canvas, I can't generate the image. However, I can create and configure my image before starting the after() loop. Also, I am able to use my canvas to delete objects canvas.delete()in my after()loop, so I still have some level of control.

I'm on windows 8.1 , using Python 3.5.4

import tkinter as tk
from PIL import Image, ImageTk
from math import floor
import numpy as np
from scipy import ndimage

root = tk.Tk()
HEIGHT = 600
WIDTH = 600
CANVAS_MID_X = WIDTH / 2
CANVAS_MID_Y = HEIGHT / 2

def my_mainloop():
    #THIS WORKS!!! REMOVES THE DIAL CREATED BEFORE THE MAINLOOP
    canvas.delete(dial_1)

    #THIS WORKS BELOW BEFORE MAINLOOP, BUT NOT IT WONT WORK! (use opencv?)
    img = dial_1_img_resized
    img2 = img.rotate(45, expand=True)
    dial_1_photo_new = ImageTk.PhotoImage(img2)
    dial_2 = canvas.create_image((dial_1_center), image=dial_1_photo_new, anchor=tk.E)
    '''CANT DRAW TO CANVAS IN AFTER LOOP'''
    print("loop!")
    root.after(4000,my_mainloop)

'''-------------------Create Canvas, and starting dials in their starting positions---------------------'''

canvas = tk.Canvas(root, width=HEIGHT, height=WIDTH, bg="black")
canvas.grid(row=0, column=0)
dial_1_path = "gauge1.png"
dial_1_width = 400

dial_1_img = Image.open(dial_1_path, 'r') #open image
dial_1_img_ratio = int(dial_1_img.size[1]) / int(dial_1_img.size[0])
dial_1_img_resized = dial_1_img.resize((dial_1_width, floor(dial_1_img_ratio * dial_1_width)), 1)
dial_1_photo = ImageTk.PhotoImage(dial_1_img_resized)
dial_1_center = (CANVAS_MID_X, CANVAS_MID_Y)

#CREATE DIAL ON CANVAS, THIS WORKS!!
dial_1 = canvas.create_image((dial_1_center), image=dial_1_photo)



'''Start Main Loop'''
root.after(0, my_mainloop)
root.mainloop()

Hence my question: is there a way to manipulate and create canvas images in a after()loop ? (called my_mainloop) Any help is appreciated!