How to change opacity of image and merge with another image in Python

Question

I've been looking up on how to put two picture together, turning the top one to around 50% transparent.

So far, I managed to find this:

from PIL import Image

def merge():
    background = Image.open("ib.jpg")
    background = background .convert('L') #only foreground color matters
    foreground = Image.open("if.jpg")

    background.paste(foreground, (0, 0), foreground)
    background.show()

But it only outputs a blank image.

Both are same sizes.

ib.jpg:

if.jpg:

desired output:

Any tips for a way to do this either with a RGB or RGBA file? I should be dealing with both types (some, in fact, have alpha layer).

Thanks,

Answer 1

You have to use blend function from PIL.Image:

from PIL import Image
bg = Image.open("1.jpg")
fg = Image.open("2.jpg")
# set alpha to .7
Image.blend(bg, fg, .7).save("out.png")