Hi Steve,
It is not a dumb question at all. There is one sensor with large and small pixels. I forgot who (panasonic?). But they have a neutral density filter over the small pixel so it is less sensitive and use it to extend dynamic range. But I suppose one could use it to enhance fine detail, though a new algorithm would have to be designed. Another method which is used on the Mars rovers is multiple sampling. For example take 10 images and because of vibrations each image is slightly misregistered from the others, and use those micro-differences to detect finer detail. Seems to work but I've never tried it myself. In non-focal length limited situations, it is easier to just increase focal length and do a mosaic.
Roger