This picture is ideal for a body stretch-morph.
The girl is standing alone with an unsharpened background and separated by a nearly perfect vertical line of the white pole of the ship. Only her hand and small part of the arm is visible on the left side of this pole and the resulting shadow. Later replace the hand of the man back on the pole.
1. Cut out body without feet.
Just use boxes, to keep it simple.
2. Stretch cut out body manually or
with percentage of about 10% – 15% (max.)
Keep an eye on the hands and feet. When they are streched it can get strange look.
(Horizontal hand may look to broad. Vertcal hand result in longer finger, wich doesen´t look weird, if they dont´t get very long.
Stretching the feet may result in a "hoof".)
3. Cut out not stretched head plus the neck, (maybe the base of the shoulder)
and bring it up the right spot.
Zoom in, so you are able to see double pixel, the one of the stretched and of not stretched picture. (In Photoshop use arrow keys for placing.)
Checking:
Switch “head-layer” from visible to invisible,
so you can notice, if the layer is on the right spot or not.
4. Now the real work starts, cleaning up the background.
“Copy stamp” is very useful tool.
But be careful with reaping patterns, like similar shapes nearby, for example waves or clouds.
In Photoshop CS5 (or higher):
Paste original head onto the stretched body.
Pick “Quick selection” and cut out new body.
This is the top layer (for now),
placing background layers under it to cover old body parts, like arm and legs.
Edit details like the fingers of the man to the left and more.
Now start to morph the body.
Or you do it before cleaning up the picture. - So you don´t have to
clean up under the bigger breast, for example. (See in 5.)
But this depends on what you want to with the picture.
Cleaning up first is good if you want to do sequences,
like more morphs of same picture.
5. Here you can see the edited parts of the original and the morphed version
Use named folders for better overview (like breast left, breast right, shadow, background …).
Especial for bigger projects this is essential.
(I was lazy and saved time here and didn´t cleaned up the layers.
But would have save time for the tutorial, later.)
Thanks for the interest.
Questions are welcome.