To add a room item photograph, first navigate to the room from the rooms list

Navigate to the room item and tap on the small camera icon within the room item heading which will activate the device camera, take your photo. 

It will auto save, then just close the camera.

You will see a thumbnail of your photo.

Tap on the thumbnail to review your photo.  Here you can delete or re-take your photo.  

You can also re-name your photo here using the caption line underneath the photo.