Build a bulk image resizer

Creating a bulk image resizer can be done efficiently using Python with the help of libraries like Pillow for image processing. Below is a detailed, fully functional Python script that resizes all images in a given folder to a specified size and saves them into an output folder.

python
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import os
from PIL import Image

def bulk_image_resizer(input_folder, output_folder, target_width, target_height, keep_aspect_ratio=True):
    """
    Resize all images in the input_folder and save them to the output_folder.

    Args:
        input_folder (str): Path to the folder containing original images.
        output_folder (str): Path to the folder where resized images will be saved.
        target_width (int): The desired width of resized images.
        target_height (int): The desired height of resized images.
        keep_aspect_ratio (bool): Whether to maintain aspect ratio or force resize.
    """
    # Create output folder if it does not exist
    os.makedirs(output_folder, exist_ok=True)

    # Supported image extensions
    valid_extensions = ('.jpg', '.jpeg', '.png', '.bmp', '.gif', '.tiff')

    for filename in os.listdir(input_folder):
        if filename.lower().endswith(valid_extensions):
            input_path = os.path.join(input_folder, filename)
            output_path = os.path.join(output_folder, filename)

            try:
                with Image.open(input_path) as img:
                    if keep_aspect_ratio:
                        img.thumbnail((target_width, target_height))
                    else:
                        img = img.resize((target_width, target_height))

                    img.save(output_path)
                    print(f"Resized and saved: {filename}")
            except Exception as e:
                print(f"Error processing {filename}: {e}")

if __name__ == "__main__":
    # Example usage:
    input_dir = "input_images"      # Folder with images to resize
    output_dir = "resized_images"   # Folder to save resized images
    width = 800                     # Desired width
    height = 600                    # Desired height

    bulk_image_resizer(input_dir, output_dir, width, height, keep_aspect_ratio=True)

Explanation:

• Pillow (PIL) library is used for opening and resizing images.

• The script scans through all image files in the input_folder.

• It resizes each image:

  • If keep_aspect_ratio is True, it uses thumbnail() which maintains aspect ratio.

  • If False, it forces the image to the exact dimensions.

• Resized images are saved to the output_folder with the same filename.

• Handles common image formats.

• Errors during processing individual images are caught and printed.

How to use:

1. Install Pillow if you don’t have it:

   nginx
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   pip install pillow
   

2. Place images in a folder, e.g., input_images.

3. Adjust input_dir, output_dir, width, and height in the script or pass them dynamically.

4. Run the script.

This script can be further enhanced with GUI, multi-threading, or CLI arguments if needed. Would you like me to add that?