PIL: Image resizing : Algorithm similar to firefox's

I resized the "original" with Python and found the same results as you did. I also resized the "original" with GIMP and I got the same (if not inferior) quality. This made me suspect that Firefox cheats. Possibly it converts to RGB ("original" mode is indexed color). Thus the following code:

import Image
im=Image.open("beta-icon.gif")
im = im.convert("RGB")
im=im.resize((36,36), Image.ANTIALIAS)
im.save("q5.png")

The result is almost as good as that of Firefox.