If a folder doesn’t contain any files, you will see a folder icon and get the follow options:
1. "Take a photo" starts the camera and lets you take pictures directly into the folder.
2. "Add files from camera" lets you upload files from your phone's camera app. (Not possible on Android 4.0.3)
3. "Add existing files" lets you upload files from your phone. (Not available on iOS)
4. "Cancel" returns you to the folder and file list.