It is a misdemeanor to both send and receive sexual images of a minor, which is anyone under the age of eighteen. It is an affirmative defense if the person who receives the image takes steps to delete the message.
http://www.capitol.hawaii.gov/session2012/bills/SB2222_CD1_.htm
Revenge porn law:
http://www.capitol.hawaii.gov/session2014/bills/HB1750_CD1_.pdf