PIL rotate image colors (BGR -> RGB)

Question

I have an image where the colors are BGR. How can I transform my PIL image to swap the B and R elements of each pixel in an efficient manner?

Answer 1

This was my best answer. This does, by the way, work with Alpha too.

from PIL import Image
import numpy as np
import sys 

sub = Image.open(sys.argv[1])
sub = sub.convert("RGBA")
data = np.array(sub) 
red, green, blue, alpha = data.T 
data = np.array([blue, green, red, alpha])
data = data.transpose()
sub = Image.fromarray(data)