CF cards are designed with flash technology, a non-volatile storage solution that does not require a battery to retain data indefinitely. They are five to ten times more rugged and reliable than disk drives including those found in PC Card Type III products.
CF cards consume only five percent of the power required by small disk drives.
This varies by digital camera vendor and by model number. The reason is that each camera may or may not use compression before they store the picture on the card. If they use compression, the amount of compression used will vary by vendor and by model number. Refer to the user manual of the specific camera or call your dealer to get specific information. No, CF Cards are designed with flash technology, which allows you to store pictures indefinitely without the need for a power source.