The new Google Photos Screensaver is on the lines of a PhotoCasting software. It can download images from RSS photostreams and show them in a slideshow.
So your grandma in another town can set the Google Photos screensaver on her desktop and whenever you upload new pictures of your daughter on Flickr, they'll display as a slideshow on her computer, automatically.
Google Photos Screensaver can fetch live photos from Flickr, Picasa, or any website that provides an RSS stream. You can also use it to view images from the latest events using the image stream of Yahoo! News. [via Google Blog]
Google Photos Screensaver version 2.0 is a 4.4 MB download available via Google Pack which is another 750kb.
Related: RSS Screensavers - Display Blog Content in your Screensaver