I hope this will show the difference. I scanned in a part of a recent painting to show you the difference in scan quality. Perhaps the web will negate the difference and I'll have to bring the files on a stick... We'll see!
The second picture is the larger file size and larger dimension and will print out a higher quality larger print. However, the first is a great space saver on your External Drive, and will be fine for most things you are planning to do with your photos.
4x6, 300 dpi, dimension of 1200 x 1800, file size 1.5MB, print out at 4x6