Step loader

Hello all

I’m just wondering what the logic is behind the stage loader idea( step loader i dunno its name)

Say i have an xml doc that i load into flash. each node has an image.
I loop through the nodes to import the image but instead of loading all the images at once the load one at a time and when ones loaded the next one does creating an anmated effect of the page filling up.

Does that make sense?

How would one go about working this out.