The video below shows the process of update a page summary (click the button on the bottom right of the video to expand the view). You can also follow the screen shots and steps below this.
2. Click on the "Images" link under "Content" on the left sidebar.
3. Then click on the "Advanced Link" under "Images".
4. Click on "View Folders"
5. A list of image folders is displayed. In order to publish a folder click "Publish" next to the folder name that you want to publish. To unpublish, Click "Unpublish".