A pixel is a little square that makes up the image on your computer screen. For example, your computer's 17" monitor has a resolution of 1280 pixels wide by 1024 pixels tall. A digital camera's CCD can only capture so many of these pixels, which are then stored in memory, and later transferred to your computer.

If a camera can capture at a resolution of 1280 x 1024 (just like the above monitor), which is a little over 1,300,000 pixels (finding out the total pixels by multiply 1280 x 1024). The word "mega" is taken from the Greek word meaning "great", and usually means "one million". Hence, a camera with 1,000,000 pixels is a 1 Megapixel camera.

Two most popular picture storage formats used by digital cameras are JPEG and TIFF. The JPEG format uses lossy compression (some data judged by the algorithm to be less important to the human viewer is discarded) to achieve small file sizes. The TIFF format uses lossless compression so no information is lost, however the pictures are typically much larger. High-quality JPEG setting is preferable for most uses.

Most, if not all, cameras have several image quality settings to choose from. They are first broken down by resolution (e.g. 2048 x 1536, 1600 x 1200, 1024 x 768, etc) and then by quality (e.g. SHQ, HQ, SQ). What's the right one to use?

The deal is this: quality is inversely proportional to the amount of JPEG compression the camera uses. Thus, a higher quality image will have less compression, and vice versa.

As you lower the quality and increased the compression, there will be more "artifacts" in your image. The artifacts are a result of the higher JPEG compression. You will notice that edges will seem blurry, or little squares will appear. See the example above for a good illustration of this.

We recommend using the middle setting for everyday shooting. If you're making big prints, consider using the highest quality JPEG level. Skip over TIFF mode, as the quality really isn't any better than high quality JPEG, but they take up much more space on your memory card.

Memory effect was a problem with older Ni-Cd batteries. This problem has been reduced with newer batteries and chargers, though how you use your batteries may also impact performance. Ni-MH batteries do not have this problem, nor do the Li-Ion batteries.

It's important to understand this difference, as you could end up mighty disappointed with the results if you get one rather than the other. 

• Optical zoom is similar to what you'll find in a regular 35mm camera: When you push the button to zoom in or out, physical lens elements move inside the camera, to achieve the desired effect.
• Digital zoom, on the other hand, has no moving parts. Using the "electronic brain" within the camera instead, the camera takes a look at what it's "looking at", and digitally zooms in, usually two to four times closer.

The problem with digital zoom is that you lose quality when you do this -- your images will tend to be more "pixelated" than the same image taken with an optical zoom camera. This is due to the "interpolation" the camera uses, which is a nice way of saying that it makes a guess about how the picture should look while zoomed in. Having optical AND digital zoom on a camera isn't bad, but we suggest try to avoid cameras with only digital zoom.

There are many reasons for this delay. The camera must:

• Set the focus, exposure time, white balance, etc.
• Charge up the CCD
  - apparently it can't hold the charge for long, so it does it right before you shoot
• Copy the image out of the CCD into RAM.
• Compress the image after it's been taken
• Write the image to the flash memory.