Picture dictation is a good way to reinforce or revise taught vocabulary. Young learners love drawing and colouring so they usually keen to do activities like this.
When you plan to do picture dictation with your kids, make sure everybody has a set of coloured pencils ready to use. A rubber also would be a good idea for them to have. You might wonder what is the big deal about having a rubber but remember little children take pride of their work and they don't want to make mistakes. So it is a big deal for them if they think their work is not perfect to have a chance to correct it.