Photos being moved first time to one of the collections are shown as New Photos to Publish.
This is the time where you can start to publish by clicking on the Publish button.
Once a photo is published, it is then moved to the Published section, indicating that this photo should be already visible on the irista Timeline.
If you have new photos that you would like to upload onto irista, just add them to any irista collection and you will be able to publish them instantly. Furthermore, if you make any changes to one of the already published photos, you can have this version on irista too, just make sure that you publish it again.