Scanning a 72 dpi is basically web safe. the only other setting you need is jpeg. If your looking for size you have to scale while your scanning not after. Heres a rule: Resolution will increase or decrease while scaling. If you take your 72 dpi image and scale it at 200 percent you will end up with an image at 36 dpi and very pixelated. If you scale that same 72 dpi image at 50 percent you have a 144 dpi image, better quality.
It is key that you get "good res" in the scanning process. industry standard is 300-350 dpi placed at 100 percent. every magazine you look at, all images are scanned at 300-350 dpi. We're talking web stuff here, but I still scan at 300 and res down after I get the size I like, thus larger posted pics at 72 dpi.
Posting close-ups? Scale while you scan! It's key!
Making any scense?
Marc Forest.
http://www.marcforest.com