Add black bars to the top or bottom of an image to make them all square (for social media like Instagram)

squareCrop.py

from PIL import Image
import glob
import os

os.mkdir(("Output"))
i = 1
for myIm in glob.glob("*.jpg"):
    im = Image.open(myIm)
    negatorX = 1
    negatorY = 1

    if im.size[0] > im.size[1]:  # Horizontal image
        size = (im.size[0], im.size[0])
        imageLoc = (size[0]//2)-(im.size[1]//2)
        negatorX = 0
    else:  # vertical image
        size = (im.size[1], im.size[1])
        imageLoc = (size[0]//2)-(im.size[0]//2)
        negatorY = 0

    back = Image.new("RGB", size)

    back.paste(im, (imageLoc * negatorX, imageLoc * negatorY))

    back.save("Output/"+str(i)+".jpg", "JPEG")
    i = i+1