You have the option of using a free viewer to see .sid format maps that you save to your computer . To use the viewer, install it on your machine. The average file size in the .sid format is 5 megabytes. You need no special viewers to view most photographs in the American Memory collections. These are of higher resolution and larger file size than .gif or .jpeg images and require a special viewer.
Some viewers offer the option of scaling the image to fit inside the viewing window.
For detailed playback information, see Video Viewer - Additional Playback Information . This format offers smaller, downloadable files and allows films to be viewed on lower-end computer systems. See a list of American Memory film collections in QuickTime format . Films presented in .mpg format are higher resolution and better quality than the equivalent QuickTime versions. The average file size for the .mpg format is about nine megabytes for each minute of film.