post factum Background behavior?

[Richmond Mathewson]

Suppose we have a stack with 20 cards already populated with all sorts 
of complicated stuff,
and then we want to spread an image across all those cards but realise 
that to copy-paste
on each card will bloat the stack ridiculously . . .

Is there a way to set an object to have background behaviour so that it 
will propagate
across a series of cards after those cards have been set up?