As they said
optimize it, use the
MDX Squisher,
BLPalettor for BLPs, and if you want to go further either use
Widgetizer, which makes the map load faster, or another
Optimizer that can be used along with Vex's, although I haven't had the chance to try this one out yet. Although make sure you read the recommended settings for each one, as there might be a way to mess your map up.
Also if one of the links don't work, the tools I listed are all on
www.wc3campaigns.net