Adding borders to an image using python

You can create a new image with the desired new size, and paste the old image in the center, then saving it. If you want, you can overwrite the original image (are you sure? ;o)

import Image

old_im = Image.open('someimage.jpg')
old_size = old_im.size

new_size = (800, 800)
new_im = Image.new("RGB", new_size)   ## luckily, this is already black!
box = tuple((n - o) // 2 for n, o in zip(new_size, old_size))
new_im.paste(old_im, box)

new_im.show()
# new_im.save('someimage.jpg')

You can also set the color of the new border with a third argument of Image.new() (for example: Image.new("RGB", new_size, "White"))

Yes, there is.

Make something like this:

from PIL import Image, ImageOps
ImageOps.expand(Image.open('original-image.png'),border=300,fill='black').save('imaged-with-border.png')

You can write the same at several lines:

from PIL import Image, ImageOps
img = Image.open('original-image.png')
img_with_border = ImageOps.expand(img,border=300,fill='black')
img_with_border.save('imaged-with-border.png')

And you say that you have a list of images. Then you must use a cycle to process all of them:

from PIL import Image, ImageOps
for i in list-of-images:
  img = Image.open(i)
  img_with_border = ImageOps.expand(img,border=300,fill='black')
  img_with_border.save('bordered-%s' % i)