How can I convert an partially alpha transparent image to have single (non-transparent) colour in PIL?

Question

I have a logo which I need to make into a monochrome version, for example all red. For example, convert this:

to this:

I've tried various techniques in PIL (mainly Image.paste), but the results do not honour the partially alpha transparent pixels around the edges.

Answer 1

from PIL import Image

image = Image.open('logo.png')
assert im.mode.endswith('A'), 'This will only work with images having alpha!'

image.load()
alpha = image.split()[-1]
image2 = Image.new(image.mode, image.size, (255, 0, 0, 0))
image2.putalpha(alpha)

image2.save('logo-red.png')