In the frame for a sale: spare-time snappers focus on the cyber galleries

Got a good eye for a picture? Alessia Horwich on the sites where you can showcase your work

Something as simple as a photograph of a landscape or an everyday scene can put you in the frame for a financial boost. Online photo libraries are easy one-stop-shops used by the likes of the BBC, Saatchi & Saatchi and even local councils to illustrate their publications. These sites allow anyone who thinks they've got a good eye for a picture to display their work. Then, if the pictures sell, the site will split the profits with the photographer, offering a bit of extra cash.

The libraries all work in a similar way: you register and then upload your photos on to the website, where they can be bought by clients. An important part of the process is choosing keywords to accompany your images, to ensure they feature high up in the site's search engine results. Additionally, before the photos go live, they will need to be approved by the site's content team. After this, it is your responsibility to manage your selection, deleting old pictures that are no longer relevant or popular, and uploading replacements that have a better chance of selling.

One site, Picturenation.co.uk, charges photographers an annual subscription fee of £10, but others, such as Alamy.com, do not levy a fee. Across all sites, you can upload as many pictures as you want, providing they meet quality standards.

Alan Capel, head of content for stock Alamy, says: "The photos do have to be of sufficient resolution – good enough for either web or print publication – and well composed. But they don't have to be up to the standard of professionals. Pictures taken with a decent digital camera – preferably single-lens reflex – should be good enough."

When it comes to the subject of the photographs, online libraries are looking for all types. There is always a need for picturesque landscapes, but there is also demand for pictures that portray aspects of ordinary life, such as recycling bins and traffic lights.

Jane Green of Picture Nation says: "We are encouraging users to have a more editorial viewpoint – to take well-composed, quality images of everyday people doing everyday things. There is a real need for these."

The profits you can make depend on the licence and the resolution and popularity of your images. Web resolution photos (72 dots per inch or higher) can sell for as little as £1, while high-resolution images (300 dpi or higher) are usually priced upwards of £50.

Pictures are bought and sold in two very distinct ways. Some are put on the market as "rights managed", which means the photographer receives royalties each time a buyer uses the image. However, the majority are sold "royalty free", which means they are sold once but used over and over again, though as the name suggests, the photographer doesn't receive a royalty payment.

Mr Capel says: "The rights-managed photos might not make a huge amount per sale, but they can sell 30 to 40 times, giving you a nice, 'passive' stream of income. But at the same time, a royalty-free photo, which can only be sold once, could be bought for an ad campaign and net big profits."

You can improve your chances of selling more often by concentrating on subjects that are not time sensitive, adds Mr Capel. "If you could take a picture that isn't going to date, you could potentially do really well because you're increasing the longevity of when that picture can sell."

All image sales revenue is split with the photo library according to their commission structure. For example, Alamy gives its photographers 60 per cent of the profits, whereas Picture Nation offers 40 per cent. This also applies to post-sale royalties.

So are these sites a genuine way for talented photographers to make extra money? Potentially, yes. Kingsley Marten, managing director of the Association of Photographers, says: "It's a market place that is open and we should embrace it.

"However, while in some respects it's good for photographers to get some pocket money, amateurs selling to stock libraries need to be careful that they are not lured into selling their images far too cheaply," he adds. "Everyone should opt to use rights managed, and if the quality of their work is good enough, they should really be paid a professional rate."

'I make roughly £20,000 a year'

Colin Palmer, 55, a structural engineer from Hertfordshire, has been selling his landscape photos through a stock library for three years. "I put around 14,000 images on and was selling roughly one per day. I did have a few cracking sales: one image of Windsor Castle was bought for $8,000 (£6,000) and used for a global ad campaign."

"The travelling isn't cheap," he says. "I have been the length and breadth of the UK and to Scandinavia. But digital means there aren't any costs for film and developing. You just need a good broadband connection and Photoshop, if you need to tweak your images before you upload them."

Sales have slowed with the recession, but he adds: "I make roughly £20,000 a year. The best way to sell more is to work on your keywords so your photos come up in the search engines."