(FORTUNE Magazine) – You know that a product has reached the mass market when you can find it in a drugstore. That's the case with digital cameras, which now show up on retail racks between the antacids and the razor blades. Kodak, Polaroid, and other major brands have introduced digital cameras for as little as $69. You can also pay several thousand dollars. How do you choose among the wide array of prices and features?

The key in a digital camera is its image resolution, defined by the number of pixels, or light points, the camera handles. More pixels means subtler and more detailed photos, ones that can be enlarged without those tiny dots' becoming visible. Cameras that sell for less than $100 usually have a resolution of 640 by 480 pixels, about the same as the average computer screen. That's good enough for, say, a small photo to display on a Website. But no one will confuse these with photos on film, which have detail and subtlety that even the best digital cameras struggle to match.

I've focused on three cameras that offer resolution of at least one million pixels (or one megapixel, in industry parlance). Up to a size of five by seven inches or so, photos from such cameras are nearly indistinguishable from film prints. If you want bigger prints, consider cameras in the two- or three-megapixel range.

Another issue is the amount of control you want. In lower-priced digital cameras, a computer typically sets shutter speed and aperture. That may be all you need if you're mostly going to take family snapshots. But if you want artistic portraits of shadows on the pond at dusk or action shots of your kid playing soccer, look for a camera that lets you adjust the exposure.

Most digital cameras include a small color LCD screen (like one you'd find on a notebook computer). These make it easy to frame your shot, especially if the subject is in poor light or is moving quickly. However, I prefer cameras that also have a traditional optical viewfinder. It can be useful in bright sunlight, which washes out the image on the LCD.

Once you take the photo, of course, you have to move the images from the camera to the computer for retouching or printing, or from the camera directly to the printer. Most digital cameras store their images on a SmartCard, a memory card about the size of a thumbnail, or a similarly small Compact Flash card. Some cameras include a computer adapter the size of a 3.5-inch floppy disk--you simply insert the memory card into a slot in the adapter and pop it into your disk drive. Several companies sell a photo-card reader that attaches to your computer's USB connector. Another option is to connect the camera to a computer's USB or serial port to transfer pictures. And some printers now have a built-in slot for the camera's memory card.

So which camera should you buy? The Canon PowerShot S10 ($999 list price; $600 street price) is a good option. It looks and feels like a 35-mm film camera, and has both a good LCD screen and an optical viewfinder. Its small size makes it easy to toss into a bag before you leave the house. Yet with 2.2-megapixel resolution, a built-in flash, and a 4X zoom lens, it can produce high-quality photos. The PowerShot stores as few as 20 large, high-quality photos or up to 200 smaller, lower-resolution pictures.

The Sony Mavica MVC-FD88 ($999 list price; street price, $700) has a floppy drive built right in, letting you avoid the hassles of transferring digital photos. (To view or edit photos, you just pop the floppy disk into your PC or Mac.) The drive makes the Mavica larger than most--its hefty handle may make you feel like a 1940s shutterbug. The FD-88 offers 1.3-megapixel resolution, a built-in flash, and a 16X zoom lens.

A good midpriced choice is the Kodak DC280 Zoom ($699 list; street price, $600). With two-megapixel resolution, it delivers good images. A 32-megabyte Compact Flash card will hold 30 to 200 photos.

Of course, the payoff with these cameras is what you can do with the photos after you shoot. You can load them into photo-editing software that comes with most cameras, like Microsoft PhotoDraw or MGI Photosuite III, to crop, enlarge, or just get rid of the red-eye from the flash. If you have a recent ink-jet printer and high-quality photo paper, you can print your own snapshots. You can post photos on Websites. Finally, you and your friends can e-mail each other photos instead of endless strings of jokes. After all, a picture's worth a thousand...