Adding Text Watermarks to Images with Python 3 and Pillow

In the digital age, protecting images with watermarks is essential, and Python provides a convenient way to automate this task.

Required tools and preparation : Ensure Python 3 is installed and install the Pillow library using pip install Pillow. Place the images you want to watermark in a single folder.

Implementation process

We will use Pillow's Image, ImageDraw, and ImageFont modules. First, define an add_watermark function that takes the image path, watermark text, and save path as parameters.

import os</code><code>from PIL import Image, ImageDraw, ImageFont</code><code>def add_watermark(img_path, text, save_path):</code><code>    img = Image.open(img_path)</code><code>    # rest of the code here</code><code># Open the image</code><code>img = Image.open(img_path)

Next, add the watermark using ImageDraw. Prepare the watermark text, font, size, and color, then draw the text at the bottom‑right corner of the image.

watermark_text = text</code><code>font = ImageFont.truetype('arial.ttf', 36)</code><code>text_width, text_height = font.getsize(watermark_text)</code><code>draw = ImageDraw.Draw(img)</code><code>draw.text((width-text_width-10, height-text_height-10), watermark_text, font=font, fill=(255,255,255,128))

Save the watermarked image with img.save(save_path). img.save(save_path) To process all images in a directory, define add_watermark_to_all which iterates over files ending with .jpg and calls add_watermark for each.

def add_watermark_to_all(folder_path, text):</code><code>    for filename in os.listdir(folder_path):</code><code>        if filename.endswith('.jpg'):</code><code>            # rest of the code here

Finally, the complete script combines these functions and runs them when the module is executed.

import os</code><code>from PIL import Image, ImageDraw, ImageFont</code><code>def add_watermark(img_path, text, save_path):</code><code>    img = Image.open(img_path)</code><code>    watermark_text = text</code><code>    width, height = img.size</code><code>    font = ImageFont.truetype('arial.ttf', 36)</code><code>    text_width, text_height = font.getsize(watermark_text)</code><code>    draw = ImageDraw.Draw(img)</code><code>    draw.text((width-text_width-10, height-text_height-10), watermark_text, font=font, fill=(255,255,255,128))</code><code>    img.save(save_path)</code><code>def add_watermark_to_all(folder_path, text):</code><code>    for filename in os.listdir(folder_path):</code><code>        if filename.endswith('.jpg'):</code><code>            img_path = folder_path + filename</code><code>            save_path = folder_path + 'marked_' + filename</code><code>            add_watermark(img_path, text, save_path)</code><code>if __name__ == '__main__':</code><code>    folder_path = '/path/to/folder/'</code><code>    watermark_text = 'My Watermark'</code><code>    add_watermark_to_all(folder_path, watermark_text)

Conclusion : Using Python 3 and Pillow, you can easily add text watermarks to individual images or batch‑process a whole directory, making Python a powerful platform for both amateur and professional image processing tasks.