Although I say I teach computer science, I sometimes think that what I really do teach is communication--between person and computer or between person and person, mediated by the computer.

Because my field of specialization is educational technology, I often speak of delivering an instructional message. I ask two basic questions:  What is it that you want to teach?  What picture / text / animation / video / interaction carries the instructional message best?

The word "teach" can just as well be traded for the more generic "say." Doing so and dropping "instructional" in the second question makes these queries very generic, applicable to practically any field.

Take, for example, children's book illustration.  I am frustrated when pictures are purely representational.  That is, they just stand for one concept.  A man standing beside a bridge. A group of people in a field.  A leaf. A kite.  Illustrations are supposed to carry the story forward.  Without even reading at the text, you're supposed to be able to tell what's happening.  Good illustrations for me are stories in themselves. Even if they are static, they are full of action.

In my office, I have two pictures on the wall. They're illustrations by Jason Moss of a Christmas story I wrote two years ago.  In the story, I described two crusty old ladies cooking Christmas dinner with two little kids, a boy and a girl, in the room.  Jason added details to the picture that I didn't imagine.  For instance, he has a dog carrying away one of the old ladies' slipper.  The old lady wriggles her toes in an attempt to grope for the missing slipper.  The little girl drags her stuffed toy and looks at the dog, not knowing whether to intervene or not.

That's a story I didn't tell--that I didn't even imagine.  Jason imagined it and told it and in so doing added depth and humor to the situation.

That's good media.