If I want to publish a book, how do I do to buy the images of the book? Do people buy all or one by one?

You would need to contact the publisher of each game (one by one) and explain to them what you have in mind. Unfortunately, if you are representing yourself and have no publishing credits, I doubt that they will take you serious or even communicate with you (other than to say NO). However, if you have a literary agent, he/she could attempt to negotiate a contract for using the images. FYI: They would never sell you the images. If anything they would offer you the one-time right to publish them.