Hi Jane,
I've had no problem texting photos to the phone number that comes in with the inquiry/booking alert. If you're not getting these as a text message, those alerts can be added from the setting menu (though not sure is this will help if they haven't booked yet). If they have booked, you can access an email address (through their contact info), paste that into an email message, then attach a photo.
Certainly, add as many well taken, descriptive photos of your place as possible!
Cheers!