Sluggish transitions between scenes problem

I’ building a Full flash site which a gallery for a set of illustations

At the moment I’ve constructed it in the following way, I’ve used scenes

A main scene with buttons to each of the other scenes. Then each scene has a forward and back button to so the user can look through the scenes consecutativly.

The main scene has a preloader with the following code

bytes_loaded = Math.round(_root.getBytesLoaded());
bytes_total = Math.round(_root.getBytesTotal());
getPercent = bytes_loaded/bytes_total;
_root.loadBar._width = getPercent100;
_root.loadText = Math.round(getPercent
100)+"%";
if (bytes_loaded == bytes_total) {
_root.gotoAndStop(3);

}

on frame 3 of the main scene are the buttons with gotoAndPlay action to the rest of the scenes.

My problem is that when I go into the other scene and try and go backwards and forwards between scenes it’s slow and sluggish.

Does this preloader script just load the main scene ? or all the scenes in the movie ?
Do I need to put preloaders between the scenes, if so how ?

Hope that make sence !!!

Cheers

Chris