Like Jeffrey said the resolution is set too low. You can see the pixels on your photo. I set mine at 2400bpi. Also, jpegs should not be too condensed. Otherwise you get to many artifacts what Jeff calls fingerprints.
I use Epsonscan software with my Epson V600 scanner. What I do when I scan is to save as a TIFF file. My 6x7 TIFF files runs about 225MB when I scan at 48 bit color. You'll probably create about 175mb files for 6x6. I'll only create the jpeg after I've done all the adjustments in Lightroom or Photoshop Elements and I'm ready to save the jpeg file. Good luck.