8 image grid with automatical image resize by screen resolution

[AlexanderO]

Hello everybody,
i am very new in python and have a problem.
I use Python 3 on a Raspberry.
I wanted to have a little program what have an full width grid with 2 rows and 4 columns. The images inside every column i want to change by Gpio later. But i stuck at the grid with the images.
I wanted to show in every field an image. This works. I decided to show images inside label (i am not sure if this is correct way).
Now i have the problem that my window is full size. Depends on screen resolution. All my Images are 800 x 800. So i want to scale them down that i have in first row 4 images and in second row 4 images.
For example when i have 1024 screen width every image must be not more then 256px.
But exactly for this i dont find solution. I read a lot and tried several ways. But no success.
In the moment the images strech all and my grid is broken.

This is my actuall code:

# import tkinter module
from tkinter import *
from tkinter.ttk import *

# creating main tkinter window/toplevel
master = Tk()
# Turn of window frame
master.overrideredirect(1)
# getting screen's width & height in pixels
screen_width = master.winfo_screenwidth()
screen_height = master.winfo_screenheight()
# New Var with Geometry size
screen_resolution = str(screen_width)+'x'+str(screen_height)
# Set size for Window
master.geometry(screen_resolution)

# Grid settings
grid.rowconfigure(master, 0, weight=1)
grid.columnconfigure(master, 0, weight=1)

# Load images
# Row 1 Standard 
imgr1 = PhotoImage(file=r"images\close1.png")
imgr1s = imgr1.subsample(1, 1)
imgr1_1 = PhotoImage(file=r"images\close2.png")
imgr1_1s = imgr1_1.subsample(1, 1)
imgr1_2 = PhotoImage(file=r"images\close3.png")
imgr1_2s = imgr1_2.subsample(1, 1)
imgr1_3 = PhotoImage(file=r"images\close4.png")
imgr1_3s = imgr1_3.subsample(1, 1)

# Row 2 Standard 
imgr2 = PhotoImage(file=r"images\close5.png")
imgr2s = imgr2.subsample(2, 2)
imgr2_1 = PhotoImage(file=r"images\close6.png")
imgr2_1s = imgr2_1.subsample(2, 2)
imgr2_2 = PhotoImage(file=r"images\close7.png")
imgr2_2s = imgr2_2.subsample(2, 2)
imgr2_3 = PhotoImage(file=r"images\close8.png")
imgr2_3s = imgr2_3.subsample(2, 2)


# Row 1
# Set images in Row 1 by Label
Label(master, image=imgr1s).grid(row=0, column=0, pady=1, sticky=N+S+E+W)
Label(master, image=imgr1_1s).grid(row=0, column=1, pady=1, sticky=N+S+E+W)
Label(master, image=imgr1_2s).grid(row=0, column=2, pady=1, sticky=N+S+E+W)
Label(master, image=imgr1_3s).grid(row=0, column=3, pady=1, sticky=N+S+E+W)

# Row 2
# Set images in Row 2 by Label
Label(master, image=imgr2).grid(row=1, column=0, pady=1, sticky=N+S+E+W)
Label(master, image=imgr2_1).grid(row=1, column=1, pady=1, sticky=N+S+E+W)
Label(master, image=imgr2_2).grid(row=1, column=2, pady=1, sticky=N+S+E+W)
Label(master, image=imgr2_3).grid(row=1, column=3, pady=1, sticky=N+S+E+W)

# infinite loop which can be terminated  
# by keyboard or mouse interrupt 
mainloop() 

Hopefully somebody can bring me to right way.
Thx for help
Alexander