To dream that someone or something is smaller than usual represents feelings of insignificance, helplessness and unworthiness. Alternatively, you may be literally trying to “knock” this person down to size. Perhaps it suggests that you or someone in your life has an inflated ego and need to be taught a lesson.
To dream that you are small and everyone is normal sized suggests that you are suffering from low self-esteem and/or a sense of helplessness. Perhaps you are being overlooked.