What is the name of nested photos with transparency?

Question

Adobe Photoshop

I apologize for not being able to properly formulate the question.
I don’t know what these types of photos are called.

I know that they are made through a paid application, but I think you can do it through photoshop.
Knowledgeable people tell me or throw an article on how to take such photos?

Answer 1

The technique is called "double exposure" (double exposure), google for these phrases.

Answer 2

Here is an example instruction

Answer 3

php.net/manual/ru/control-structures.foreach.php
php.net/manual/ru/control-structures.if.php

Answer 4

array diff

Answer 5

use foreach