Digital photography has gone from being a minority interest to a mainstream hobby in the space of three years.

Now people are keeping archives of their photos on their computers rather than simply on paper and are looking for other things to do with their images rather than just flick through them every once in a while.

There are lots of uses for your digital photographs. Editing them and printing them out is the most obvious and still the most common but why not use an image as Windows wallpaper, display them on a website or use them to sell unwanted items on an online auction site?

Whatever you decide to do with your photographs, there are specific things you can do to them to ensure you get the best results for whatever you are trying to achieve.

Print shop
Despite the huge numbers of people switching to digital photography, most folks still want a paper print to show off rather than just a file on their computer.

Getting photo prints is as easy as pressing the print button in your image-editing program if you have a good printer, but many people would still rather take their images to a high-street photo lab and get them printed in the traditional way.

Whichever way you decide to print your photos, you need the best quality images you can get. That means setting your digital camera to its highest quality mode.

Although this means you'll get less photos on your camera's memory card, it will mean your images will have the best chance of looking good when they are printed out.

If your camera offers an option to save captured images as uncompressed Tiff files, this is the best option for the very best quality images.

Tiffs really eat into your camera's memory though, so it's best to only switch to these when you are taking pictures you'd like reproduced very large.

Just how good your images will look depends to a large extent on the quality of the camera you have.

Digital camera quality is measured in megapixels. This isn't the only thing that will affect print quality, but it gives you an indication of how good your prints are likely to be.

Cameras rated up to 1.3 megapixels are unlikely to produce really sharp, impressive results when printed out, but for standard 6x4in photo prints they should be acceptable.

Two and three megapixel models should produce very good 6x4in prints with better models managing sharp 7x5in prints too. As the megapixel rating goes up, the size at which the image will look sharp will go up too.

If you want to put your photos to more use than just sitting in an album, the requirements can change again. If you're planning to blow an image up to poster size, then you want to hold on to as much quality as possible.

A high megapixel camera and top-quality resolution settings will ensure this. As a rough rule, three megapixels is fine up to 12x8in and five megapixel images will blow up to poster-sized prints.

Share and share alike
Traditional photo albums are going out of fashion now, thanks to the internet. If you want to share your images with friends and family, publishing them on a website is neither as daunting nor as expensive as you might think.

There are dozens of good photo-sharing websites to choose from but you may be signed up for two of the more familiar ones already.

If you have a Hotmail or Yahoo email account, free space to store some images is supplied as standard.

Yahoo supplies its users with a very generous 30MB of space and is fairly straightforward to use. MSN gives Hotmail account holders only 3MB of space but is very simple to use, thanks to integration with Windows XP's web publishing wizard.

These websites will automatically resize your images for you too, so you can get as many images on as possible, and both allow you to buy more space if you can't get all your snaps up in the free space provided.

Your pictures can also be set so that only people with the appropriate password can view them.

Online opportunities
Whether you are putting photos on your own website or need to upload your images onto a site such as eBay, there are some important tips which can help ensure success.

Any image which is going to appear on a website needs to be kept as small as possible. This ensures that download times are kept to a minimum and people looking at the picture don't get bored before it has fully appeared.

Another thing to ensure is that your image is saved in the appropriate format. Jpeg is the most multi-purpose format and is the safest bet if you aren't sure.

Using images on eBay really helps to sell items in the auctions. The auction website is a good place to go in search of bargains, but any item on sale will attract more bids if there's a picture to illustrate it. If you're keen to get your stuff sold, a good picture is the key to success.

To post the image of your product on the gallery, it needs to be in either Jpeg, BMP or Tiff format. eBay recommends that you use a Jpeg image as this is the smallest and is the format that most digital cameras use.

When you list an item on eBay, you are allowed one image free, with subsequent pictures costing around 10p each.

If you are selling something small, one image should be fine but if it is a large or expensive item, investing in several pictures showing different angles or points of interest could help your sale.

As the images on eBay are quite small, it makes sense to ensure that the object fills your photo. If there is lots of background and the object is a small blob in the middle of the photo, it will be difficult for buyers to see and they may look elsewhere.

It's in the mail
If you don't fancy posting pictures on a website, another use for digital images is emailing them to friends and family, but there are a few things to check before you start bombarding your buddies.

If your images are from a digital camera, the file sizes are probably too large to send. Online photo-sharing sites have been created to prevent this problem but, if you are determined to email your images, there are a few things you should do first.

The first thing is to ensure that the file sizes are kept small. Another good tip is to only attach two or three images to each email. Having multiple, large attachments often causes problems.

If you have lots of images to send, compressing them into a single file can also help. Using WinZip is one way of doing this but Windows XP users have it easy.

Select all the photos you want to compress, right-click on the selection and click Send to and then Mail recipient. The Emailing Photo wizard will guide you from here to make sure your images are a suitable size for sending.

Desktop DIY
Personalising your Windows Dekstop image is very easy. Right-clicking on an empty part of the Windows Desktop and choosing Properties will bring up a dialogue box for changing your wallpaper.

Any Jpeg, BMP or Gif image can be used, although BMPs are generally discouraged as they are large files that can slow your PC down.

A common problem with using your own images is that they often aren't the right shape. Windows can stretch images to fit the screen, tile images which are very small across the screen, or centre images so that they sit in the middle.

The way to get the best results is to ensure that the image you want is roughly the right shape and size. You should ideally use a rectangular (landscape) image shape so that it will fit proportionally across the screen.

In terms of size, you can be exact and crop the image you want to use to the same dimensions as your screen resolution (usually 800 x 600 or 1024 x 768).

You can double-check this in your Desktop properties. This means that you'll be able to see the entire image filling the screen without Windows stretching or cropping things. If the resolution of your image is too low, it will look grainy; too high and it will slow your PC down.

Icons
If you're a fan of personalising your applications with your own icons, then you'll know that they need to be fairly small in size.

AOL Instant Messenger has hundreds of pre-designed icons to choose from, including cartoon characters, film stars and much more. But did you know that you can make your own?

Once you have signed in to AOL Instant Messenger, click on My Aim in the toolbar and select Edit Options and then Edit Preferences. Select Buddy Icons from the left-hand side and you will be presented with a full list of icon options.

To add your own, simply click on the Browse button to add the image from your PC. As the icons used are so small, an ideal image will be something simple with a file size of 7KB or less. You can crop or resize any image to a suitable size and, once again, Jpeg is the best file format to use.

If you are using Windows XP Home, custom login icons can be built in the same way. The standard images that come with XP are under 7KB in size and at a resolution of 48 x 48 pixels.

Once again, simple images work best as the icon is very small. Crop the picture to make the most of the foreground subject and the small file size you are using.

ID card photos
If you are submitting your own photographs for official documents, it is always worth double-checking for any specific requirements. If you want to submit your own digital photo for your passport, then visit the Home Office website, which provides guidelines for you to follow.

Its main requirement for photographs is that you take a head and shoulders shot, centred on a white background and printed on glossy, high-quality photo paper. It also requests that your pictures are 800dpi, which seems very high.

It is, however, hoping to revise the guidelines later in the year. We think that a good-quality photo printed at 300dpi is unlikely to be rejected. Until the rules change, the choice is yours.

Following these procedures will save you time and most of the rules are common sense. Sending photos of you wearing sunglasses or pulling funny faces is a sure way to have your pictures sent straight back to you.