There are two main types of photography to sell, that is assignment photography and Stock Photography. Assignment photography is taking photographs of a predetermined event, and stock Photography is taking photographs in the hope that you will be able to find a future buyer. Most professional photographers take both types, the weddings and portraits take care of immediate bills, as they command a higher price, because they are generally only of interest to a limited number of people. There are exceptions like being hired for a specific assignment to photograph an Olympic Event, and then being able to sell that photograph Internationally. In general, stock photographs command a lower price, but they are more saleable to a wider base.Stock photographs’ are generally sold on the Internet through what is known as “Stock Libraries”. They generally all work on a very similar system, you take photographs and submit them to a stock library and they sell them to interested parties such as travel brochure companies, advertising agents, book publishers. This way of marketing photographs has distinct advantages, if you are a part time freelancer, or have just started your own business. Either way you are probably too busy making portfolios, and taking pictures to market them. Another factor, which makes this method of marketing advantageous, is that when you are starting you do not have the network of contacts to market your photographs. Added to that there are some people who won’t or can’t perfect their marketing skills.A downside of this marketing method is that there is a little more to it than taking photographs and waiting for the Royalty cheques to come in. Most stock libraries, will want to re-caption your pictures to fit in with their image, this can be a time consuming process and it can take months to get them online. Like many aspects of selling it is a “numbers game”, the more photographs you have available to sell the more you are likely to sell. This is a fairly general aspect of marketing, but it is more specific in this instance, as prospective buyers may look at other images, if they like one particular one. Because of the time factor of getting your work to the buyers or the public, many stock libraries, have insisted on a minimum contract, which means that they typically ask to retain your work for a minimum of two years.Some of the stock libraries are general and some are more specific. Marine Themes obviously specialise in underwater photography, and they scan and correct all their images before sale. They are then color corrected to ensure that any prints will be the best quality. All this takes time, to get the images actually for sale on the Internet. The benefit is that marine photography is highly specialised, and this process does increase your chances to merchandise your work.In the past the market was limited to buyers who were sent colour brochures and made their selection from them, now the market is expanding, as many libraries have widened their sales base by allowing customer’s to make their purchases directly on line. This factor alone has increased the numbers game the more people who have access, the more who are likely to buy. Some stock libraries are general and some are highly specific such as South African images. Some cover specialist areas such as marine photography, or nature.So how do you choose the stock library that will be the most beneficial to you? There are independent reports covering the various strengths and weaknesses. The annual Freelance Photographer’s Market Handbook in the UK features a section on stock libraries and is an excellent reference guide. Some of the stock libraries have been established for ten years. They have hundreds of photographer’s and hundreds of thousands of images. As a result of this they may be reluctant to take on new clients. However if you have a large portfolio available immediately it may be worth trying one of the older companies. However you will be competing with established photographers who have built up a client base. Many of the new companies have less than a hundred photographers and you will start by being a bigger fish in a smaller pond.At the end of the day, the choice has to be your personal decision, and there is nothing to stop you from registering with more than one library. Whilst the market is growing and will continue to grow to encompass on line sales, remember to consider that sales from a printed catalogue will be important for a while, and it may be advantageous for you to choose a library with a well referenced catalogue.Every stock library has different terms and conditions. In general most give you a straight 50% of the earnings. However some do let the images go into the hands of “sub agents”, and they will expect an additional cut from any sales. Read your contract well before you sign and beware of copyright issues. Normally when the photograph is sold the buyer is issued with a license number, which only allows them to use the image the once. You minimise your royalties if you allow a buyer to pay once and then get multiple uses out of it.All in all if you are prepared to look at your market strategy over a long period of time, stock libraries offer you an option. There are forums for professional photographers that do address the issue, and it may be worth you looking into othe peoples style and work. Here are some I recommend you look into and consider selling your stock through:- PhotoStockPlus and Photo.comThere are also available a huge number of royalty free sites. You may question why buyer’s would consider paying for an image whilst they can obtain other’s free? The answer here is that royalty free photographs don’t make them free, you do purchase them, but you have the rights to re-use the stock photos and CDs for as many different projects and clients as you wish without paying further licensing fees.