I am a teacher of computer graphics at a local high school. I agree with both sides of the issue. Glossy prints do provide a sharper image when scanned. Most photo scanning software (especially Adobe Photoshop) will try to soften the texture of a matte finish scan. It will make your images appear to be slightly out of focus. The other side to this is that glossy prints will show fingerprints extremely bad so scan them as soon as you get them before your friends get their fingers on the prints. Fingerprints can create color shifts in the scan and can also create unwanted hot spots on the scan.