JPG (pronounced, Jay peg) is a file format used for storing and displaying images. It’s the most common format online, only really challenged by GIF.

JPG is the acronym for Joint Photographic Experts Group. It has the apparent disadvantage that when you save a picture in the format it loses some data. This is caused by JPGs compressing the image, which may seem a major drawback. However, the format does preserve a lot of information even in high compressions which makes it ideal for screen viewing.

Most digital cameras save images by default as JPGs. In most case though, you do have some choice over the degree of compression used.

Even inexpensive point-and-shoots will have a menu giving a choice of picture quality in their armory. Please note, this is not about “resolution” which measures the number of pixels in the image. The image quality you set determines by how much the picture will be compressed, so how much quality is lost.

There is a further trade-off in that the higher the quality, the more space the picture will take on your memory card. Remember, you can always use another memory card, but you can never recover the loss of quality in the image.

The bottom line is the use you intend for the final picture. Web pages and emails are best served by low quality pictures. Making prints from the image requires the highest quality obtainable at source.

If you’re taking JPG images in a high-quality compression, how many will you be able to squeeze onto your memory card? That’s a question often asked.

Here’s rough guide to what you can expect from a variety of memory card capacities:

1 MP (megapixel)
32MB card: 91
64MB: 182
128MB: 356
256MB: 731
512MB: 1420

3 MP
32MB: 26
64MB: 53
128MB: 106
256MB: 213
512MB: 421

5 MP
32MB: 12
64MB: 25
128MB: 51
256MB: 102
512MB: 204

These numbers may vary according to how your camera processes images, so use as a general guide only.

If you’re new to digital photography here are Ten Top Tips for buying a digital camera:

1. Price: This can vary from around $100 to upto $10,000 for a high end professional camera. You can buy one with good resolution and options for under $600. Ones with more manual control settings can be found for around $600-2000 dollars, usually suited to serious amateurs.

2. Resolution: To print good quality color photos at the standard film sizes 4″x6″ or 5″x7″ you’ll need a 1-2 megapixel camera. If you are printing as large as 8″x10″ then you’re going to need a higher resolution around 2-3 megapixels.

3. Viewfinder: Low-end digital cameras provide an optical viewfinder while more expensive ones replace the viewfinder with a LCD (Liquid Crystal Display). Look towards purchasing one with an LCD display. Kodak make digital cameras with superb displays so have a look at those.

4. Focus: Most cameras are either fixed-focus or autofocus which is suitable for the average digital camera user. With a fixed-focus lens everything from a few feet to infinity is in focus. The only problem with this is when shooting pictures up close. Autofocus will automatically bring whatever is in the centre of the viewfinder into focus.

5. Storage: Many cameras come with a small memory card, but if you want to take lots of pictures or footage, it is a good idea to check whether what is supplied is enough. Chances are it won’t be, so look at how much a new ‘decent’ capacity memory card etc is going to cost for that particular model.

6. Compression: If you want the highest possible image quality, look for a camera that will let you save pictures in “CCD raw mode” which means with no compression at all.

7. Batteries: It is important to get a camera that will accept rechargeable batteries. There are three varieties of batteries available Nickel Cadmium (NiCad), Nickel-Metal Hydride (NiMH) and Lithium-ion (Li-ion or LiOn). A camera may accept only one or two kinds of batteries so be sure to find out what kind.

8. Power Saving: To save battery power, use a camera that accepts an AC adaptor.

9. Interface: If you are interested in maximum speed you should keep your eyes open for cameras and card readers that support FireWire

10. Video Output: This can be invaluable for presentations. If you would like to do this, look for a camera with a video-output terminal. It allows you to display your pictures on a TV or projector.

By David Crossley of www.digitalcamerasinfozone.com ( All the information you need on buying your next digital camera ).