I recently completed this commissioned portrait of a young man with his (recently deceased, I believe) grandmother.
The challenge was to combine these two different photographs. I was a little worried about how well they would mesh together, since the lighting is different on each one. But I think that the drawing ended up looking pretty natural, like the young man and his grandmother are really standing side-by-side.
I've discovered like I like drawing elderly people. They may not be as easy to draw, like babies, but their faces have a lot of character.