These pictures are known as "Glyphs" and first showed up on posters and online as part of the viral marketing for Fringe. Even though there only seem to be a few glyphs, depending on where the particle of light appears in the image makes many variations of the glyphs, and they all correspond to letters of the alphabet.
For more information about the individual Glyphs, see the article on Fringepedia:
http://fringepedia.net/wiki/Glyphs
For a detailed article on The Observer and screen captures of his appearances:
http://www.fringepedia.net/wiki/The_Observer
You can find a listing of the songs played during the show, including scene descriptions, here: http://tvshowmusic.com/shows/fringe-music-season-4
go to tunefind.com website,there you can find songs played specifically for each episode of lots of tv series
http://www.tunefind.com/
This episode is actually an extra episode from season 1 that was shown during season 2.
An F.B.I. agent is forced to work with an institutionalized scientist and his son in order to rationalize a brewing storm of unexplained phenomena.
Who are the characters in Fringe?
Olivia Dunham, Walter Bishop, Peter Bishop, Astrid Farnsworth, Aaron Sneddon, Abby Stockton, Agent Rodriguez, Agent Tim, Alt Lincoln's Father, Alternate Astrid Farnsworth, and others
