Images must be scanned at 300 dpi (lpi) and be printed at or below the size at which they were scanned. (In other words, you cannot scan a 2x2 image and make it 4x4 on your book's page - it must be 2x2 or smaller.)
If images are to be enlarged after scanning, remember that the dpi goes down as the image is enlarged. A safe practice for scanning images that will be enlarged is to scan them at 600 dpi (lpi) to allow for a moderate enlargement.
If you are not comfortable scanning images yourself, ask your representative for a quote and to have us do
the scanning for you.