As an example, if your scanner has an area of 8.5''x11'' and you scan a document at 200 DPI, the resulting image will have a resolution of 1700x2200. DPI determines the resolution of the image that will be created when you scan something. The most important option is the dots per inch, or DPI, setting. Picking the right settings can save you time and storage space. There are a few important options available to you when you're setting up your scan settings.