I'm showing you how to add by your smart phone.
1. Take a photo you wish to add.
2. Find the place by searching in Google Maps app your smart phone.
Press on Google Maps icon
Type the name of the place in search box
Press on the red point.
5. Press on "Publish" then Done. Then photo will upload to that place.
That photo will need some time to approve by Google Team.
Do this to share the world with your photos.