Those shots are pretty good, much better than I get using a microscope adapter on my camera (lighting is my problem.) For the price those USB microscopes are fantastic. Have to be careful which you buy, the specs vary a lot.

BTW don't bother with digital zoom except for getting a convenient sized live picture. All it does is crop the image then resize using interpolation, it doesn't reveal any more detail (if anything it loses some.) You are better off cropping and resizing in a graphics package.