It's always great to add some climbing and overview pictures of the crag too. This gives everyone a better idea of the crag as a whole and is a great inspiration for other climbers too.
You can add photos by going to the "photos" section in the crag navigation bar and clicking "Share your photo from ... ".
By adding climbing pictures to the crag you can also choose them as the cover pic of the topo. Without them, there will be a random topo image chosen for the cover of the topo.
To choose the cover picture, go to "Edit" and "edit crag details". Select the picture you'd like to be used as a cover.