Well, If u are using Photoshop's save for web, quality around 60, tweak around with the colour base....Thats the damn best reduction u can get. Photoshop's the best. Consider buying. The CS2 version also works HDRI. I save all my max renders as HDRI now. Real cool. Too bad poser don't have any support for HDRI. Saves quite some time getting exposure right. :)