Flash - Some digital cameras have variable settings such as on, off, fill and red eye reduction. Typically used for group shots. You may display photographs directly from the camera. This feature allows you to display the images in locations where a computer is not available. Optional power supply - This is highly recommended.
Digital cameras use batteries at an alarming rate.
If you are taking several shots indoors and use a tripod, it is suggested that you use the power supply. Any prolonged use of the LCD panel for viewing or deleting photographs in the camera should be done while connected to a power supply. Last but certainly not least, the camera requires the most power while images are being transferred to a computer. If the batteries loose power during the transfer process, damage may occur to the camera or cause files to be lost. You should only use the power supply that is designed to operate your particular camera.