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
from PIL import Image, ImageDraw, ImageFont
def add_watermark(img_path, text, save_path):
img = Image.open(img_path)
# rest of the code here
# Open the image
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
font = ImageFont.truetype('arial.ttf', 36)
text_width, text_height = font.getsize(watermark_text)
draw = ImageDraw.Draw(img)
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):
for filename in os.listdir(folder_path):
if filename.endswith('.jpg'):
# rest of the code here

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

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