Better colour change method for smaller file size?

Hi, I’m new to Flash but eager to learn! I hope you guys can give me some good tips on using better code to reduce file size.

I’ve just done a colour change swf for a friend who has a clothing business. Basically it just needed to change the colour of the t-shirt according to button presses.

I just wanted to know if there is a better way (more code i assume) to do the colour changes? I’m looking for a really compact file size because there’s a lot more to go in it yet! – this is the swf I’ve got so far… – and that’s the source file.