The ex is right: the secret to compositing is finding the right photos and seeing the potential. In this case, both dropped in my lap and wiggled. This started out as an exercise in using the Select & Mask feature. Then I thought I could make this into a lesson for my advanced class. Then it took on a life of its own. It was a fun experience but involved a moderate to high level of Photoshop fluency and problem solving: being able to to know when to use selections and masks; blend modes; smart objects; filters; tools and brushes; and layers. I’m not sure I can teach that without creating an impossible assignment.