"Do we need a higher Pixels camera?", "Image quality depends on the number of Pixels?", "Larger Sensor got higher Pixels than smaller Sensor?"...and etc. Most people ask this questions when they choosing a camera.
One day, my friend complaint that he got cheated by the salesman because the salesman told him the model he bought is the highest Pixels in the market, at that moment. When he tried to capture sceneries, the pictures is not clear while he zoom in the LCD monitor. He tried to focus, change the Depth of Field, changing to lower of Pixels and tested with different ISO speeds and etc but the result still same, dissatisfy.
Well, what he bought is "higher number of Pixels" but not "higher Sensitivity Sensor" ( or we called it a "Large Sensor"). I remember once awhile in the market, companies were competing for "higher Pixels" camera because most people want a "higher Pixels" instead of a "higher Sensitivity Sensor" (they might not even know what is higher sensitivity sensor). Most people thought "higher Pixels" camera is so important.
Actually, even if a smaller sensor has the same number of Pixels as a larger sensor. A larger sensor are more sensitive, resulting in a higher image quality than a smaller sensor. Therefore, higher image quality does not depends on the number of Pixels only.
Assume we have 2 same sensitivity sensors but different number of Pixels, which one will have a higher image quality? Well, of course is the higher number of Pixels. But, compare a 10 Mega Pixels in higher sensitivity sensor and 12 Mega Pixels in lower sensitivity sensor, I bet the first choice is better, for sure :)