They didn't quite filter it out the images:
http://images.google.cn/images?q=tiananmen&svnum=1 0&hl=zh-CN&lr=&cr=countryCN&start=80&sa=N>

Google and China can *never* filter out the truth completely. Meanwhile, scientists and other bussiness persons in China can work with the rest of the world, letting rights trickle in one research paper at a time.

-John