Downloading Images with Python's Requests Library

In this tutorial, we will explore how to download images from the web using Python’s popular requests library. This is a fundamental skill for any web developer or data scientist who needs to work with online images.

Introduction to the Requests Library

The requests library is a lightweight and intuitive way to make HTTP requests in Python. It provides an easy-to-use interface for sending HTTP requests and interacting with web servers.

Downloading Images

To download an image using requests, you need to send a GET request to the URL of the image and then save the response content to a file. Here’s a basic example:

import requests

url = "http://example.com/image.jpg"
response = requests.get(url)

if response.status_code == 200:
    with open("image.jpg", 'wb') as f:
        f.write(response.content)

In this example, we send a GET request to the specified URL and check if the response status code is 200 (OK). If it is, we open a file in binary write mode ('wb') and write the response content to it.

Streaming Large Images

However, this approach can be problematic when dealing with large images, as it loads the entire image into memory. To avoid this, you can use the stream parameter of the requests.get() method:

import requests

url = "http://example.com/large_image.jpg"
response = requests.get(url, stream=True)

if response.status_code == 200:
    with open("large_image.jpg", 'wb') as f:
        for chunk in response.iter_content(1024):
            f.write(chunk)

In this example, we set stream=True to enable streaming. We then iterate over the response content in chunks of 1024 bytes using the iter_content() method and write each chunk to the file.

Using Response Raw File Object

Alternatively, you can use the response.raw file object to download the image:

import requests
import shutil

url = "http://example.com/image.jpg"
response = requests.get(url, stream=True)

if response.status_code == 200:
    with open("image.jpg", 'wb') as f:
        response.raw.decode_content = True
        shutil.copyfileobj(response.raw, f)

In this example, we set stream=True and use the shutil.copyfileobj() function to copy the contents of the response.raw file object to the destination file.

Best Practices

When downloading images using requests, keep in mind the following best practices:

• Always check the response status code to ensure that the request was successful.
• Use binary write mode ('wb') when writing image data to a file.
• Consider using streaming to avoid loading large images into memory.
• Be mindful of the chunk size when iterating over the response content.

By following these guidelines and examples, you can effectively download images from the web using Python’s requests library.