front is lower res VGA cam meant for video conferencing - that's why the image is smaller - you'd be seeing the rest of the screen of the other person. Biggest image size supported by VGA cam is 640 x 480 equiv to less than one half a megapixel so only really suitable for a wallet size print.
Unsure if there is a hack, but you wouldn't be able to increase its quality anyway - increasing size would just degrade the image.