If you've recently added new photos to your linked photo account (Google Photos, Flickr, etc.), they may not immediately show up on DAKboard. Depending on the photo service, it may take up to a few hours before DAKboard pulls in the latest photos.
However, this is not the case with Dropbox. The Dropbox is able to notify DAKboard that a change has been made as soon as you add or remove photos. So any new photos will be available to be displayed on DAKboard within a few minutes. Unfortunately, none of the other photo sharing services provide this functionality.