images.py

import os

from PIL import Image
from fpdf import FPDF

# Author: @NavonilDas

# Example to Append all the images inside a folder to pdf
pdf = FPDF()

# Size of a A4 Page in mm Where P is for Potrait and L is for Landscape
A4_SIZE = {"P": {"w": 210, "h": 297}, "L": {"w": 297, "h": 210}}
# pdf may produce empty page so we need to set auto page break as false
pdf.set_auto_page_break(0)

for filename in os.listdir("images"):
    try:
        # Read Image file so that we can cover the complete image properly and if invalid image file skip those files
        img = Image.open("images\\" + filename)

        # Read Width and Height
        width, height = img.size

        # Close opened Image
        img.close()

        # Convert Width and Height into mm from px as 1px  = 0.2645833333 mm
        width, height = float(width * 0.264583), float(height * 0.264583)

        # Check if Width is greater than height so to know the image is in landscape or else in potrait
        orientation = "P" if width < height else "L"

        # Read the minimum of A4 Size and the image size
        width = min(A4_SIZE[orientation]["w"], width)
        height = min(A4_SIZE[orientation]["h"], height)

        # Add Page With an orientation
        pdf.add_page(orientation=orientation)
        # Add Image with their respective width and height in mm
        pdf.image("images\\" + filename, 0, 0, width, height)

    except OSError:
        print("Skipped : " + filename)

pdf.output("output.pdf", "F")