Overlay extracted head back onto original image

Given the code attached, it extracts and aligns a head from an image. I want to modify this extracted head and then past it back onto the original image. The code below needs modified to include the bounding box of the extracted part, and code to overlay it back onto the original image. Also attached is the test image. I do not want the code modified to change the shape, size or anything else. A GAN expects this exact input.