Compact cameras use really, really small sensors to capture images. To squeeze all those pixels onto such a small sensor, something has to give. Each pixel is like a microscopic lens, and each pixel is separated by a little wall, called a Septum. The septum is supposed to keep light from falling over from one pixel to another. But to make room for more pixels, the septums have been removed from high-resolution sensors. This causes lower contrast and digital noise (AKA grain). You may be able to make big blow-ups with your 12MP compact, but they won’t look as good as manufacturers want you to believe.