A person on a surfboard riding a wave. Foams water just add water.
A large wave is coming into the water / A wave that is crashing on the side of a boat / Public domain stock photo of a ship.
This image is from Pixabay and was published prior to July 2017 under the Creative Commons CC0 1.0 Universal Public Domain Dedication license https://web.archive.org/web/20161229043156/https://pixabay.com/en/service/terms/ . In July 2017, Pixabay switched the old sitewide license for all uploads from Creative Commons CC0 to a custom license arrangement that does not meet the Creative Commons CC0 1.0 Universal Public Domain Dedication license terms.