Erin Bas gives a good definition of Pictado. The key sentence is in italics:
It is just like a Dictado (Dictée – see the category), but the students listen and draw. Sometimes I have them number off six boxes, sometimes it’s more free-style. I like the quiet and focus it brings to a class. A good follow-up is to have them repeat the story to a partner using their Pictado pictures, then write as much as they can remember for each picture they drew. If they’re feeling it, I let them add the details. If not, I just dictate it while they draw or write what they hear.