Python Pillow - Adding Borders to an Image

Adding borders to images is one of the common task in image processing. Borders can help to frame the content, draw attention to specific areas, or add a decorative element. In Pillow (PIL) the expand() method of the ImageOps module is used to increase the dimensions of an image by adding a border or padding around it. This can be helpful for various purposes such as adding a border, creating a canvas of a specific size or resizing the image to fit a particular aspect ratio.

The expand() method

The expand() method is useful for adding borders to images and adjusting their dimensions while maintaining the aspect ratio. We can customize the size and border color to suit our specific requirements.

Here's the basic syntax for the expand() method −

PIL.Image.expand(size, fill=None)

Where,

• size − A tuple specifying the new dimensions i.e. width and height for the expanded image.

• fill (optional) − An optional color value to fill the border area. It should be specified as a color tuple (R, G, B) or an integer value representing the color.

Following is the input image used in all the examples of this chapter.

Example - Expanded Image with Border

In this example we are using the expand() method to create the expanded image with the border.

from PIL import Image, ImageOps

#Open an image
image = Image.open("Images/handwriting.jpg")

#Define the new dimensions for the expanded image
new_width = image.width + 40  
#Add 40 pixels to the width
new_height = image.height + 40  
#Add 40 pixels to the height

#Expand the image with a white border
expanded_image = ImageOps.expand(image, border=20, fill="red")

#Save or display the expanded image
expanded_image.save("Output_Images/expanded_output.jpg")
open_expand = Image.open("Output_Images/expanded_output.jpg")
open_expand.show()

Output

Example - Expanding Image with Blue Border

Here this is another example we are expanding the image border with blue color by using the expand() method of the Image module.

main.py

from PIL import Image, ImageOps

#Open an image
image = Image.open("Images/handwriting.jpg")

#Define the new dimensions for the expanded image
new_width = image.width + 40  
#Add 40 pixels to the width
new_height = image.height + 40  
#Add 40 pixels to the height

#Expand the image with a white border
expanded_image = ImageOps.expand(image, border=100, fill="blue")

#Save or display the expanded image
expanded_image.save("Output_Images/expanded_output.jpg")
open_expand = Image.open("Output_Images/expanded_output.jpg")
open_expand.show()

Output