expressInstall.swf - this is the swfobject flash player that is embeddedand runs the slideshow player.

flashvars- These are the parameters that are set for the flash player to run the slide. This includes the name of the slideshow to be played, settings to display a title and the popcorn method to be called for loading the slideshow.

params- parameters on how the slideshow player will behave. In this case, the slideshow player allows for full screen display of the slideshow player.