how the class works

[berckut72]

Hello!
I wrote a very small program and created a class in it for loading pictures without defining methods. I was surprised to find that the part of the code that is in the class is executed without calling the class - the "print" operator worked. I would like to know - should it be so? If this is correct, then why is this happening?

import os
import tkinter as tk
from tkinter import*
from PIL import Image, ImageTk

root = tk.Tk()

class ImageInst:
    bild_list_image     = []#список картинок здания

    '''загрузка картинок строения в bild_list'''
    path = 'C:\\ws5_class\\general\\bilds\\'
    for i, filename in enumerate(os.listdir(path)):
        if filename.find("bild") == False:
            if (filename.endswith(".png") or filename.endswith(".PNG")):
                path1 = path + '\\' + filename
                im = Image.open(path1).convert('RGBA')
                im_01 = ImageTk.PhotoImage(im)
                bild_list_image.append(im_01)
    print('bild_list_image: OK')


root.mainloop()