Your original image may be in various formats: slide, transparency, book, photo, map, poster, etc. Depending on the format and size of the original, you must decide which method of digitizing the image (converting it to a computer file) will work best for you. Common digitizing machines include the flatbed scanner (for photos, books, and artwork), slide scanner (for 35 mm slides and film negatives), transparency scanner (for large format negatives or overhead transparencies), and digital camera (for extremely large originals or as an alternative to film camera). These devices are available at no charge from various departments of UIC; see "UIC Resources" at end of this document for further information.

Most computer monitors cannot display over 72 dots per inch ("dpi", also referred to as "ppi" or "pixels per inch"), so your end "web-ready" product shouldn’t be more than that resolution. You will probably want to scan it at a much higher resolution and reduce it later for several reasons. The first reason would be if you intend to use the image for another application. Print especially requires much higher dpi than the web. The typical laser printer prints in 300-600 dpi, and if you plan to print the image, you should scan it at least 300 dpi. Another reason you may want to scan at a higher resolution would be for archival purposes.

How big your scan should be may be the most crucial decision you make in the scanning process, and will likely require some experimentation until you get the results you want. Obviously, you must scan it large enough to read it, especially in the case of maps, diagrams or other images with detailed information. Many people use thumbnails or reduced-size imagemaps, which link to larger, more detailed images. It is best to try to keep images as small in size as possible. Try not to make your users download images over 100k, if at all possible.