Solve the nonogram.
Final answer is
or perhaps I should say
I confess that I only bothered going this far by strict logical inference
before allowing myself to make the obvious assumptions about the structure of the solution, leading to this (where white and yellow should now be treated as equivalent):
whereupon it's clear how to get to the solution at the top.
Gareth McCaughan solved this, but here's an animation of the solution: