Poor lenses primarily cause chromatic aberration and distortion which are not the problems we're seeing. The issues of image quality that come up with photos posted on our forum revolve around color balance, under exposure, motion blur and lack of focus. Of course better cameras (both point and shoot and slrs) have white balance settings, greater light sensitivity, image stabilization and other features that help but great images can be made with simple cameras. High resolution cameras are certainly essential in print advertising (I'm a catalog photog and I shoot with a 40 mp Phase One back on a Hassie) but completely unnecessary for web posts. Besides, you'd be hard pressed to find a camera made today under 10 mp. I could make fine images for this forum with a 1 mp camera if I could find one. The information you need to do that has been laid out clearly and concisely in this thread.
Photography is my passion, truth my obsession. No wait, Stieglitz said that.
Cheap Shots is my tumblr photoblog
22.5 OTS Weber kettle
Smokey Joe (RIP)
a dorky little headlamp