I have a photo where I want to replace the head, I cut the head from another photo, how can I integrate this head to not see that it is photoshop work. I am in the design a complete zero.
The trouble with this "simple" head replacement is it is simultaneously the easiest & the hardest thing to do in Photoshop. Plonking one head over another is easy… except it looks bad even if you manage to cleanly cut the original [better than your example & as Billy is trying to show you from YouTube].
Once you have that basic skill, the next pratfalls are size/scale, direction, lighting & colouration.
In your example, the only match out of the box is direction.
It's possible your replacement head is looking in the same direction as the one you're replacing. Unfortunately, that's where it ends.
It's too big - he has a lollipop head, poor guy.
The original subject is in bright & very directional lighting; medium strong from front right, & very strong from behind. Compare the brightness & colouration of his left arm & knuckles [camera right] with his right arm & the highlights out far left.
Your replacement guys is flat lit from the front… & basically has no 'orange' at all, he's almost blue by comparison, & has little shadow.
This is going to need some colour manipulation - the easy bit - & some airbrush skills - the hard bit.
You need to add shadows & colouration to match that of the original body. As whilst you're working on this you can see the original head, you can use that for cues as well. We can't, it's hidden.
Let me show you this as an example of one I never quite managed to get right. The overlay was looking in approximately the right direction & I could scale him to fit.
Lighting, however, was from completely the wrong direction, & seriously orange.
I ended up with this - not hugely happy. It would have done as a meme, but not as 'proper' work.
[I'm going to claim this qualifies as 'fair use']*
Normally I'm pretty good at this type of thing, but in this case I had no control over input images, I had to take what I could get from the interweb. [Normally I do my own photography for the replacement face, so i can design the lighting to match before compositing.]
To see roughly how it was done, we have the original frame, cleanup of the original head, then an unmodified overlay…
The majority of the work then was to match lighting direction & colours, done with a brush, adding shadows & highlights.
Not a great result, but as I said at the start… the hardest thing to do in Photoshop.
*Purposes that may support a finding of fair use include:
Teaching, including private study or classroom use.
Criticism or commentary.