It is not currently possible to add a photo or other attachment through the Goboony messaging system. Once the booking has been confirmed, however, you are able to send a photo or other attachment via e-mail or even Whatsapp.
Once a booking is confirmed you will be able each other's contact details including email addresses.
✔️ Your details are only visible to Travellers once a booking has been confirmed
✔️ You are able to send emails directly to a Traveller once they have confirmed a booking with you