Save a NumPy array as an image file using Python

Last update on April 29 2025 12:54:11 (UTC/GMT +8 hours)

19. Save Array as Image File

Write a NumPy program that saves a NumPy array as an image file (e.g., PNG) using an image processing library like PIL or opencv.

Sample Solution:

Python Code:

from PIL import Image
import numpy as np

# Create a NumPy array with random values
array_data = np.random.rand(100, 100, 3) * 255
array_data = array_data.astype(np.uint8)

# Define the file name to save the image
image_file_name = 'saved_image.png'

# Convert the NumPy array to an image object
image = Image.fromarray(array_data)

# Save the image object to a PNG file
image.save(image_file_name)

# Verify by loading and displaying the saved image (optional)
loaded_image = Image.open(image_file_name)
loaded_image.show()

Output:

Explanation:

Import Libraries:

Imported Image from the PIL library for image processing.
Imported numpy as np for handling arrays.

Create NumPy Array:

Created a 100x100 NumPy array with random values scaled to the 0-255 range.
Converted the array to uint8 type suitable for image data.

Define Image File Name:

Set the file name for saving the image as saved_image.png.

Convert Array to Image:

Converted the NumPy array to a Pillow image object using Image.fromarray.

Save Image File:

Saved the image object to a PNG file using the save method.

Verify by Loading and Displaying:

Optionally loaded the saved image using Image.open and displayed it using show to verify the saved file.

For more Practice: Solve these Related Problems:

Write a Numpy program to convert a numeric array into an image and save it as a PNG file using an image processing library.
Write a Numpy program to generate a heatmap from a 2D array and export it as an image file in PNG format.
Write a Numpy program to modify a grayscale image stored as an array and then save the modified image with a new file name.
Write a Numpy program to create an RGB image from three separate arrays and then export the combined image to a PNG file.

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