1) add another layer on top of the picture1 that you want to
place the face on.
2) from there other picture 2- you can choose to use clone or
select cut and paste to pic1.
3) go back to the pic one layer of the head, you need to blow up in
to pixel to remove all the edge of the head nicely. Then, u need to
create some shadows. Next is to adjust the head skin tone &
lighting to match the body and neck skin tone. As you most properly
still have to recreate the effect of the lighting and how shadow
fall on the face to match the lighting angle and shadow.
4) finally merge the 2 layer into 1. Then use the smurge tool to
merge the neck area better, do some casusian blur and sharpen it
again.
