Perhaps delivering high resolution images to US/ Western geeks is not their primary mission. Perhaps a few low res snapshots to keep the western media off their back (see, we really did it, put away your conspiracy theory stories) is all they felt obliged to do.
Maybe there's a high res camera sending pictures back to their scientific research / military people and they just don't feel the need to distribute this material to the general public in other countries. The Chinese funding model might not be the same as the USA's, maybe they don't need to distribute high res holiday snaps to ensure continued funding.
Perhaps there's no high res camera on board because the science of the mission doesn't need any more than a few low res snaps. The real work might be elsewhere. I've read a couple of articles that note that the lander is much bigger than you might expect for a rover of this size, so it might be the real mission here is to test lander technologies in preparation for sending a manned mission. It might be that the real science is around testing that platform, and the rover is just supplementary, a nice addition for extra kudos and you might as well do it while you're there.