In the early days of computing, if you left a monitor on for a long time a ghostly image of whatever was on the screen would be burned into it. Even when the monitor was off, you could still see the image burned into the screen's phosphor. To prevent this, the screen saver was introduced. When a computer was left unattended for a preset period of time, a series of images were displayed one after another so the screen burned in evenly. One of the earliest hits that you saw everywhere for a while was an animated screen saver with colorful flying toasters. The screen saver served more than a utilitarian function, it added personality to people's computers. Although no longer needed to prevent screen burn-in, screen savers live on for their entertainment value. They also hide confidential information and look better than a word processor or spreadsheet. One of the delights of digital photography is that you can use your own images as a screen saver or package them to share with friends and customers. You can even sell them as fund raisers for a school or organization. There are two kinds of screen saver applications.

• On your own system. There are applications, including one built into your operating system or available free from Google that display images on your system as a screen saver. These programs let you specify a folder on your system and any images in that folder are then displayed much like a slide show when the computer is inactive for the specified period. To change the photos in the screen saver, you just change the photos in the specified folder or specify another folder.
• On other systems. There are applications that create screen savers for distribution. Generally you create a screen saver much like you create a slide show. You specify the order in which images are displayed or have them appear randomly, specify their size, how long each is on the screen, the transitions between images, and other aspects of the show. When finished, the program converts the images into a screen saver format and stores it, on Windows systems, as a file with the screen saver extension .scr and on Mac with the extension .dmg. You can then install the screen saver on your own system or share it with others so they can install it on theirs. When looking for one of these applications, here are some features to look for:
• Does the program give you the right to distribute or sell royalty-free versions? If not, how much do you have to pay for these rights?
• What file formats are supported?
• Can you include videos as well as still images? Can you synchronize music?
• Does the program create versions in the desired screen resolutions of 640 x 480, 800 x 600, or 1024 x 768? Keep in mind that some people are using 640 x 480 or 800 x 600 screen resolutions and plan accordingly.
• What transition effects are there?
• Can you add captions or other text?
• Can you insert links that viewers can click to visit your Web site?
• Does the program create screen savers that automatically install themselves on a computer?
• Can you position and move images on the screen to control the layout?
• Does the program advertise itself on the screen saver you create? Do you need to pay to remove the message?