Digital cameras store their photos in something called a memory card. This small, thin, removable card is installed in the camera. When you take your photos the image is recorded and stored on the card. The number of images you can store depends on the size of the memory in the card and at the resolution your photos are taken. Low resolution photos take up less memory than high resolution shots.
Memory cards are available in assorted capacities from 16 megabytes to about two gigabytes. When the card is full you can take it from the camera and download the images to a computer or a printer. You can then erase the images from the card and use it again and again. Having a spare memory card is also a good idea. There are various kinds of memory cards and they are rated at different speeds.
You should turn your camera off when you are loading or unloading a card, but make sure you don't unload a card or turn the power off when the camera is saving a photo. Before you buy a memory card make sure it will work in your model camera.
Depending on the size and type, memory cards can range in price from about $15 to $700.