Useful if you can draw:

If you pose in said photo, I will illustrate it.

Who does not want an selfie illustrated by The Oatmeal?

This growth hack would not work for most things.

Sure, not everybody can copy this verbatim. 

What about the same thing, which betabrand is doing: http://www.betabrand.com/?m=12208Model citizen campaign. Share pictures of people in their closing and let the people share it.

Works for people, who can't draw.

In general give people things they want to share, and they will share those things.

Growth hack:

The right way to get people share your product is to make it about them. Put the people in the center and inject your product into sharable content about people. Then let the people do the work.