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.