Preloader problem

Hi,
I’m new to flash and I’m trying to add a preloader to a site I’m working on. I’ve got several stock photos that I’ve imported into seperate swf files that are selected randomly and loaded into an area on my layout. All of that is working fine and the file sizes of the images were small( around 55-60k each). Now that I’ve added a preloader to each of the images, the file size has ballooned to around 680k each. What happened?? Does simple actionscript add that much filesize? Is there anything I can do to reduce the size?

Thanks,
AJMoore