The best way to change the order of photos in a slideshow is to put them in an album. As you create your album, you can put the photos in any order you would like. Once you create the album, you can use the “View Slideshow” link on the album detail page to see your slideshow:
You can use the “Get Embed Code” link below “View Slideshow,” or the “Share” link in the lower right-hand corner of the slideshow, to add it to other pages on the Ning Network or to other sites.
To change the order of photos in your album once it’s been created, go to the album’s page and click the “Edit Album” link.