Rudegar, the link you present here is all about PhotoStream. And PhotoStream is related to iOS devices only.
I am guessing the question relates to iPhoto on a Mac or PC..
To see stuff from your Mac/PC on your Apple TV you can use Airplay or use Homesharing. Since Homesharing is defined to iTunes only, I'm afraid that it will be limited to music and movies only.
On iPhoto for Mac and for Windows, I see in Preference a Sharing tab a way to turn on Sharing. So after turning on Sharing in iPhoto I go to my Apple TV, Menu>Computers, and then I see my default Shared Library, hoping to see my photos…. But no, it still only contains Music, Movies and TV shows...
So my conclusion is that there is no direct way to use Apple TV to show photos on your Mac/PC. Sad, but true...