Preloader questions - I know, again!

I have a technical question about preloaders. I have 6 swfs, each of which load a series of jpg images in a photogallery. I have a main movie, which then randomly loads these swfs as backgrounds, so each time someone visits the site they get a different picture. (Scotty walked me through this one earlier). Now, what I want to know is: if I put a preloader on my main movie, will it preload the appropriate jpegs in the swfs (that are randomly loaded)? or: how do i ensure that the jpg images load into the swf that is currently being loaded? Do I need to worry about whether the jpegs have loaded into those swfs? Or should i be putting in 2 different preloaders. One in the (random) swf and one in the main movie? The jpg images in the (random) swfs are quite large, btw!

Thanks…

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