While the Ecomartists app initially received permission for all photos being used. It is possible a customer will see their photo and complain. If this happens, take down the AD or Product page using the photo Immediately! Then notify the Ecomartists team, so we can remove the photo from any products as well.
Its important to be respectful of people wishes.
Ultimately it is your store and your responsibly to prevent any issues, the Ecomartists app is not liable for behavior on your store.