Bobby Neel Adams has an interesting photography project: “Two photographs of the same person, from different periods of time (child and adult) are spliced together.”
I can’t truly recreate the effect of their project for myself without a lot more work, but the idea of two different pictures from completely different ages is interesting.
2019 update: Can’t find the image I created for this. I’m curious now what I was doing. There’s a guy named Ard Gelinck doing some ‘family picture’ type portraits of celebrities with their younger selves here on Instagram.