How do I convert a numpy array to (and display) an image?


I have created an array thusly:

import numpy as np
data = np.zeros( (512,512,3), dtype=np.uint8)
data[256,256] = [255,0,0]

What I want this to do is display a single red dot in the center of a 512×512 image. (At least to begin with… I think I can figure out the rest from there)

Asked By: jlswint



Using pygame, you can open a window, get the surface as an array of pixels, and manipulate as you want from there. You’ll need to copy your numpy array into the surface array, however, which will be much slower than doing actual graphics operations on the pygame surfaces themselves.

Answered By: Stefan Kendall

The Python Imaging Library can display images using Numpy arrays. Take a look at this page for sample code:

EDIT: As the note on the bottom of that page says, you should check the latest release notes which make this much simpler:

Answered By: ars

Note: both these APIs have been first deprecated, then removed.

Shortest path is to use scipy, like this:

# Note: deprecated in v0.19.0 and removed in v1.3.0
from scipy.misc import toimage

This requires PIL or Pillow to be installed as well.

A similar approach also requiring PIL or Pillow but which may invoke a different viewer is:

# Note: deprecated in v1.0.0 and removed in v1.8.0
from scipy.misc import imshow
Answered By: Peter Hansen

The following should work:

from matplotlib import pyplot as plt
plt.imshow(data, interpolation='nearest')

If you are using Jupyter notebook/lab, use this inline command before importing matplotlib:

%matplotlib inline 

A more featureful way is to install ipyml pip install ipympl and use

%matplotlib widget 

see an example.

Answered By: Steve Tjoa

You could use PIL to create (and display) an image:

from PIL import Image
import numpy as np

w, h = 512, 512
data = np.zeros((h, w, 3), dtype=np.uint8)
data[0:256, 0:256] = [255, 0, 0] # red patch in upper left
img = Image.fromarray(data, 'RGB')'my.png')
Answered By: unutbu

Using pillow’s fromarray, for example:

from PIL import Image
from numpy import *

im = array('image.jpg'))
Answered By: user3322286

How to show images stored in numpy array with example (works in Jupyter notebook)

I know there are simpler answers but this one will give you understanding of how images are actually drawn from a numpy array.

Load example

from sklearn.datasets import load_digits
digits = load_digits()
digits.images.shape   #this will give you (1797, 8, 8). 1797 images, each 8 x 8 in size

Display array of one image

array([[ 0.,  0.,  5., 13.,  9.,  1.,  0.,  0.],
       [ 0.,  0., 13., 15., 10., 15.,  5.,  0.],
       [ 0.,  3., 15.,  2.,  0., 11.,  8.,  0.],
       [ 0.,  4., 12.,  0.,  0.,  8.,  8.,  0.],
       [ 0.,  5.,  8.,  0.,  0.,  9.,  8.,  0.],
       [ 0.,  4., 11.,  0.,  1., 12.,  7.,  0.],
       [ 0.,  2., 14.,  5., 10., 12.,  0.,  0.],
       [ 0.,  0.,  6., 13., 10.,  0.,  0.,  0.]])

Create empty 10 x 10 subplots for visualizing 100 images

import matplotlib.pyplot as plt
fig, axes = plt.subplots(10,10, figsize=(8,8))

Plotting 100 images

for i,ax in enumerate(axes.flat):


enter image description here

What does axes.flat do?
It creates a numpy enumerator so you can iterate over axis in order to draw objects on them.

import numpy as np
x = np.arange(6).reshape(2,3)
for item in (x.flat):
    print (item, end=' ')
Answered By: Hrvoje

Supplement for doing so with matplotlib. I found it handy doing computer vision tasks. Let’s say you got data with dtype = int32

from matplotlib import pyplot as plot
import numpy as np

fig = plot.figure()
ax = fig.add_subplot(1, 1, 1)
# make sure your data is in H W C, otherwise you can change it by
# data = data.transpose((_, _, _))
data = np.zeros((512,512,3), dtype=np.int32)
data[256,256] = [255,0,0]
Answered By: user140536
import numpy as np
from keras.preprocessing.image import array_to_img
img = np.zeros([525,525,3], np.uint8)
Answered By: Sivasai

this could be a possible code solution:

from skimage import io
import numpy as np
Answered By: Aman Bagrecha

For example your image is in an array names ‘image’

All you do is


This will display an array in the form of an image
Also, dont forget to import PLT

Answered By: abbujaansboy