Convert png files to one pdf, with transparency replaced with white colour

main.py

"""
Convert png files to one pdf, with transparency replaced with white colour
"""
import glob
from PIL import Image

IMG_FOLDER = "rez"
files = []
for img in glob.glob(f"{IMG_FOLDER}/*.png"):
    rgba = Image.open(img)
    rgb = Image.new("RGB", rgba.size, (255, 255, 255))  # white background
    rgb.paste(rgba, mask=rgba.split()[3])  # paste using alpha channel as mask
    files.append(rgb)

files[0].save(
    "out.pdf", "PDF", resolution=100.0, save_all=True, append_images=files[1:]
)