Extending an image (PIL/Pillow)

Question

I can use the following code to draw a black strip (or rectangle) atop a base image:

base_width, base_height = img.size
background = Image.new('RGBA', (base_width, base_height/3),(0,0,0,146))
offset = (0,base_height/2)
img.paste(background,offset,mask=background)

Result:

But how do I extend the height of the image such that the said black strip appears attached below the image's bottom border, outside the image itself ?

If I move the offset in my code above, the black strip can't move beyond the borders of the base image, so that's not a viable solution.

Answer 1

Here's one way:

1. Create a new_img that is (base_width, base_height + background.height) in size
2. Paste the original img into new_img at (0, 0)
3. Paste the background into new_img at (0, base_height)