The visual stream shows a thumbnail gallery of the most recently received images, as they flow into the project. You can navigate to past images, page by page (and you can choose how many thumbnails to show on each page).
When you click on an image it pops up in a lightbox display. You can use left- and right-arrows to navigate back and forth through the gallery of images with that display.
Two filters can be used to narrow down the gallery according to the source of data: by a given session, or by one or more authors (i.e. the person who uploaded the image).