Web page preloader?

Hiya.

On my website, the photo galleries are all using the Lightbox script to display the images a scroll through them which runs brilliantly. The only problem with the script, is that EVERYTHING has to be fully loaded on the page in order for it to work. If a picture is click before everything is loaded, it simply loads the picture in another page instead of using the lightbox.

What i’m looking for is a preloader (I think) to cover the entire page in a dark overlay, with a loader bar in the middle, which just displays until everything has loaded. Once it is loaded, the page becomes active again and everything can be used as normal. I was hoping for one that looked like the loader on the lightbox itself?

It isn’t made in Flash.

Thanks