What do resolution or DPI mean?
It is important to understand how scanning resolution, or DPI, affects your digital images. Increasing the scanning resolution, in essence, magnifies the resulting digital image while retaining the original photo quality. What does this mean for you? It means the primary reason for needing higher DPI is to enable larger reprints (i.e. printed enlargements) in the future. Also, if you plan on projecting or otherwise displaying your photos on a big screen, increasing the resolution above 300DPI may be beneficial.