I subscribe to Grow Curriculum (https://growcurriculum.org), and they recently released (most) of the stuff for the upcoming school year. I didn't want to scale all the images manually, and created the TripleHead2Go collages myself. So, this script came into existence.

image-processing.py

import sys
import os
import glob

from os import path
from PIL import Image

glob_pattern = 'C:/Users/evoris/Grow Curriculum/2019-2020/02 Curriculum/**/Graphics & Video/Horizontal/'

for graphics_dir in glob.iglob(glob_pattern, recursive=True):
    if os.path.isdir(graphics_dir):
        # create "scaled" directory
        scaled_dir = graphics_dir + '/Scaled/'
        if not os.path.isdir(scaled_dir):
            os.mkdir(scaled_dir)
            # start a new image for the th2g size
            th2g_image = Image.new('RGB', (3840, 720))
            # walk the directory to get the image files
            for root, dirs, files in os.walk(graphics_dir):
                for file in files:
                    # scale and save images at 720p
                    image = Image.open(os.path.join(root, file))
                    tn_image = image.thumbnail((1280, 1280), Image.ANTIALIAS)
                    image.save(scaled_dir + file, subsampling=0, quality=100)
                    im_subject, im_direction, im_series, im_curr = file.split('_')
                    if im_subject == 'BackgroundSlide':
                        #add it to the th2g image
                        th2g_image.paste(image, (0, 0))
                        th2g_image.paste(image, (2560, 0))
                    elif im_subject == 'TitleSlide':
                        th2g_image.paste(image, (1280, 0))
                    image.close()
            th2g_image.save(scaled_dir + 'TH2G_' + im_series + '_GrowStudents.jpg', subsampling=0, quality=100)
        else:
            print('Scaled directory already exists: ' + scaled_dir + ' (Skipping)')