Just like a conventional camera, a digital camera has a series of lenses that focus light to create an image of a scene, But instead of focusing this light onto a piece of film, it focuses it onto a semiconductor device that records light electronically - a computer then breaks this electronic information down into digital data. All the fun and interesting features of digital cameras come as a direct result of this process. 

Instead of film, a digital camera has a sensor that converts light into electrical charges - these are either CCD or CMOs sensors.

The amount of detail that the camera can capture is called the resolution, and it is measured in pixels - this resolution depends on the quality of the CCD/CMOS sensor. The more pixels a camera has, the more detail it can capture and the larger pictures can be without becoming blurry or grainy.

Some typical resolutions include:

256x256 - Found on very cheap cameras, this resolution is so low that the picture quality is almost always unacceptable. This is 65,000 total pixels

640x480 - This is the low end on most "real" cameras. This resolution is ideal for e-mailing pictures or posting pictures on a Web site

1216x912 - This is a "megapixel" image size (1,109,000 pixels) - good for printing pictures

1600x1200 - With almost 2 million total pixels, this is "high resolution" - you can print a 4x5 inch print taken at this resolution with the same quality that you would get from a photo lab

2240x1680 - Found on 4 megapixel cameras - this allows even larger printed photos, with good quality for prints up to 16x20 inches

4064x2704 - A top-end digital camera with 11.1 megapixels takes pictures at this resolution - at this setting, you can create 13.5x9 inch prints with no loss of picture quality

Just as with film, a digital camera has to control the amount of light that reaches the sensor. The two components it uses to do this, the aperture and shutter speed, are also present on conventional cameras.

In addition to controlling the amount of light, the camera has to adjust the lenses to control how the light is focused on the sensor. In general, the lenses on digital cameras are very similar to conventional camera lenses -- some digital cameras can even use conventional lenses

Storage
Most digital cameras have an LCD screen, so you can view your picture right away. This is one of the great advantages of a digital camera - you get immediate feedback on what you capture.

Digital cameras use a number of types of storage cards, these are like reusable, digital film - Storage cards used include SmartMedia, CompactFlash, Memory Stick & XD

No matter what type of storage they use, all digital cameras need lots of room for pictures. They usually store images in one of two formats - TIFF, which is uncompressed, and JPEG, which is compressed.

When you have captured the images on the camera you can print them out on a photo printer or at a high street store (using you storage card) or transfer them to your computer using a cable or cards reader - using a computer photo album to save them for future viewing or editing.