PIL: fromarray gives a wrong object in P mode

Question

I want to load an image in P mode, transform it into np.array and then transform it back, but I got a wrong Image object which is a gray image, not a color one

label = PIL.Image.open(dir).convert('P')
label = np.asarray(label)
img = PIL.Image.fromarray(label, mode='P')
img.save('test.png')

dir is the path of the original picture; test.png is a gray picture

Also, it's because you discard the palette. You have to open in 'P' mode, not convert to it. — Mad Physicist, May 21 '18 at 14:30
What happens if you do `label.save('preconvert.png')` immediately after your first line? — Mad Physicist, May 21 '18 at 14:31

Mark Ransom · Accepted Answer · 2018-05-21T15:10:39.433

2

Images in 'P' mode require a palette that associates each color index with an actual RGB color. Converting the image to an array loses the palette, you must restore it again.

label = PIL.Image.open(dir).convert('P')
p = label.getpalette()
label = np.asarray(label)
img = PIL.Image.fromarray(label, mode='P')
img.setpalette(p)
img.save('test.png')

edited May 21 '18 at 15:10

answered May 21 '18 at 14:34

Mark Ransom

299,747
42
398
622

score -1 · Answer 2 · answered Jul 01 '23 at 17:20

-1

(I cannot comment, on the above post) Small correction on the above code: img.putpalette(p) (instead of setpalette)

answered Jul 01 '23 at 17:20

mespinosa

7
2

This does not provide an answer to the question. Once you have sufficient [reputation](https://stackoverflow.com/help/whats-reputation) you will be able to [comment on any post](https://stackoverflow.com/help/privileges/comment); instead, [provide answers that don't require clarification from the asker](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead). - [From Review](/review/late-answers/34627377) – Koedlt Jul 06 '23 at 04:24

PIL: fromarray gives a wrong object in P mode

2 Answers2

Linked