In movies how do they make photographs with a character from an earlier time like childhood and such?

Photoshop

Actual childhood photos + photoshop.

They would either doctor a copy of an old photo provided by the actor, or just have something suitable shot by a photographer and altered as necessary. In the old days they'd use airbrushing, now it could just be photoshopped.

Sometimes they use pictures of the adult actor when they were younger, and sometimes it's another actor.

I think alot of editing amd look alikes go into that particular work if im not mistaken.

Most people, including actors, have pictures of themselves from throughout their lives.