I am about to scan about 200 4x6 photographs and don't want to scan them at too high a resolution. (To keep file size and scan time to a minimum) I am creating a slide show with music to be shown on a portable LCD projector for a grade school. (Volunteer work of course) I began scanning last night at 300 dpi but have a feeling that is overkill. What is the optimal scanning resolution? TIA! Dean