My niece had never seen her paternal grandfather (he died before she was born) so when I had an opportunity to borrow a photo of him for scanning, I jumped at the chance. Here's the way the snapshot looked when scanned at 1200 dots per inch on my home scanner (a Canon, with accessories for scanning slides as well as photos/documents):
Picasa, I cropped to show just Grandpa's head and the baby he's holding.
I was actually lucky: This photo had no thumb-tack holes, dust fluffs, or smudges to be retouched out. Now future generations will know what Grandpa looked like while holding his first grandchild, only 4 months old! And the whole process took just a couple of minutes, with freebie software.