tiler.py

from PIL import Image
from random import randint

default_image_name = "tile_default.png"
attention_image_name = "tile_attention.png"

output_image_name = "tile_output.png"

tile_size_pixels = 64

new_image = Image.new("RGB", (1024, 1024))
default_tile = Image.open(default_image_name)
attention_tile = Image.open(attention_image_name)

for row in range(0,16) :
    for column in range(0,16) :
        dice = randint(0,15)
        if dice >=14 :
            paste_image = attention_tile
        else :
            paste_image = default_tile

        new_image.paste(paste_image, (row*64, column*64))

new_image.save(output_image_name)

So I had to create an image of 1024x1024 pixels , consisting of loads of 64x64 pixel tiles. The tiles had to be randomly chosen from 2 tiles (default and attention in the code) with a preference for the default image.