Convert an integer array to a PNG image in Python

Question

I've been trying to convert an integer array of RGB values to a PNG image. How can I generate the following image from the following integer array?

enter image description here

'''This is a 3D integer array. Each 1D array inside this array is an RGBA value'''
'''Now how can I convert this RGB array to the PNG image shown above?'''
rgbArray = [
[[255,0,0], [255, 0, 0], [255, 0, 0], [255, 0, 0], [0,0,255], [0,0,255], [0,0,255], [0,0,255]],
[[255,0,0], [255, 0, 0], [255, 0, 0], [255, 0, 0], [0,0,255], [0,0,255], [0,0,255], [0,0,255]],
[[255,0,0], [255, 0, 0], [255, 0, 0], [255, 0, 0], [0,0,255], [0,0,255], [0,0,255], [0,0,255]],
[[255,0,0], [255, 0, 0], [255, 0, 0], [255, 0, 0], [0,0,255], [0,0,255], [0,0,255], [0,0,255]],
[[0,0,255], [0,0,255], [0,0,255], [0,0,255], [255, 0, 0], [255, 0, 0], [255, 0, 0], [255, 0, 0]],
[[0,0,255], [0,0,255], [0,0,255], [0,0,255], [255, 0, 0], [255, 0, 0], [255, 0, 0], [255, 0, 0]],
[[0,0,255], [0,0,255], [0,0,255], [0,0,255], [255, 0, 0], [255, 0, 0], [255, 0, 0], [255, 0, 0]],
[[0,0,255], [0,0,255], [0,0,255], [0,0,255], [255, 0, 0], [255, 0, 0], [255, 0, 0], [255, 0, 0]],
]

Questions asking us to recommend a tool, library or favorite off-site resource are off-topic for Stack Overflow as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it. — tckmn
– tckmn, Commented Jul 8, 2013 at 15:27
@Doorknob Yikes... I'm afraid that your comment will encourage other users to downvote my question. :( They're going to assume that I haven't made a substantial effort at solving my own problem, and they're going to downvote my question for that reason. :/ So far, I've created an integer array of RGB values and I've asked what I should do in order to create a PNG image from this array. Does this constite a lack of adequate research effort on my part? — Anderson Green
– Anderson Green, Commented Jul 8, 2013 at 15:29
@Doorknob I don't see any part of this question that is asking for a library recommendation. An appropriate answer is likely to contain one, but that doesn't make this a bad question. — Mark Ransom
– Mark Ransom, Commented Jul 8, 2013 at 15:36
@MartijnPieters, since PIL isn't part of the standard Python distribution it's unreasonable to expect everyone to have heard of it. You should leave an answer. — Mark Ransom
– Mark Ransom, Commented Jul 8, 2013 at 15:38

Martijn Pieters · Accepted Answer · 2013-07-08 15:47:03Z

7

You can use the Python Imaging Library to convert RGB datapoints to most standard formats.

from PIL import Image

newimage = Image.new('RGB', (len(rgbArray[0]), len(rgbArray)))  # type, size
newimage.putdata([tuple(p) for row in rgbArray for p in row])
newimage.save("filename.png")  # takes type from filename extension

which produces: PIL output

The .save() method can also take a format argument, PNG would fix the output to PNG.

(I recommend you install the Pillow fork as it is more actively maintained and adds proper packaging and Python 3 support).

answered Jul 8, 2013 at 15:47

Martijn Pieters

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Mark Ransom · Accepted Answer · 2013-07-08 15:41:43Z

1

The Python Imaging Library (PIL) is handy for most imaging needs in Python. The Image module contains a fromstring function and a save function that should do exactly what you're looking for.

answered Jul 8, 2013 at 15:41

Mark Ransom

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