Your scan looks like it has a lot of JGP "compression", Rick. Check to see what "quality number" your graphics program is saving these as. They usually range from 0 to 10, with 0 the most compression. More compression, smaller file size, but you lose in the number of gradations of color and brightness. Look at the 'halo' around your chips from the shadow; there are only 3-4 different shades. Not a problem in itself, but indicates the software is compressing a lot of shades into one.

As a practical matter, I have begun saving most of my scans for display at quality zero; they still look fine. So that may not be your only difficulty. Inexpensive scanners inherently produce poorer scans. If you paid less than $100, that may be part of the problem as well.