Create a custom sizegrip style

sizegrip.py

import tkinter as tk
from tkinter import ttk
from PIL import Image, ImageDraw, ImageTk


def sizegrip_style(background, foreground):
    """Create style configuration for ttk sizegrip

    Args:
        background (str): The color used for the background.
        foreground (str): The color used for the grips

    Returns:
        dict: The settings used to update the sizegrip style.
    """
    image = create_sizegrip_image(foreground)
    settings = dict()
    settings.update({
        'Sizegrip.sizegrip': {
            'element create': ('image', image)},
        'TSizegrip': {
            'configure': {'background': background},
            'layout': [('Sizegrip.sizegrip', {'side': 'bottom', 'sticky': 'se'})]}})
    return settings


def create_sizegrip_image(color):
    """Create assets for size grip
    Args:
        color (str): The hexadecimal color to use for drawing the widget.
    """
    im = Image.new('RGBA', (14, 14))
    draw = ImageDraw.Draw(im)

    # draw the grips
    draw.rectangle((9, 3, 10, 4), fill=color)  # top row
    
    draw.rectangle((6, 6, 7, 7), fill=color)  # middle row
    draw.rectangle((9, 6, 10, 7), fill=color)

    draw.rectangle((3, 9, 4, 10), fill=color)  # bottom row
    draw.rectangle((6, 9, 7, 10), fill=color)
    draw.rectangle((9, 9, 10, 10), fill=color)

    # could also save the image here... im.save(filepath)
    return ImageTk.PhotoImage(im)


if __name__ == '__main__':
    root = tk.Tk()

    style = ttk.Style()
    style.theme_use('default')
    sg_settings = sizegrip_style(background='#fff', foreground='#000')
    style.theme_settings('default', sg_settings)

    sg = ttk.Sizegrip(root)
    sg.pack(fill='both', expand='yes')
    root.mainloop()
    
    

Np. Glad it was helpful.