we all know that Google's affects your page rank with the load time of a page. How? That's part of the secret sauce. But we know that page speed is a serious factor.

So -> what is considered the speed of a page?

Is it just the first (and main) html file which the GET receives? Or does it also include loading of images as part of that speed.

so for example...

GET /index.htm <- takes 0.45 seconds to retrieve (including DNS lookup before).

robot parses page.. see's there's a single main image....

GET /img/main.png <- takes 5 seconds to download.

is the page speed for that resource, 0.45 seconds OR 5.45 seconds?

I understand Javascript is not fired .. but are any of these external resources all downloaded and part of the page speed?