We know that the larger a sensor size is, for a fixed Mega-Pixel count, the better the picture quality is. One reason is that there is a larger surface area to capture more light for each pixel. This is why they say a DSLR can have better quality pics than a compact camera due to its larger sensor size for a similar mega-pixel count.
One thing I wonder though, within the same camera, will changing the resolution setting between Large, Medium and Small change the quality of the pics (other than for enlarging purposes)?
Since the sensor size for the camera is already fixed, and if I do not need such a large resolution photo, will changing the setting from Large to Medium resolution improve on the picture quality (less mega-pixel count per sensor surface area)?
Or is it somehow the density of pixel per surface area is already fixed in a sensor, and changing the resolution setting only activates more or less of the pixels already fixed in the sensor?