Unless you are a photographer yourself, then like most people, you will naturally turn to stock photo websites where you can buy royalty-free professional images. The most well-known stock photo website is iStockphoto, an excellent but relatively expensive source. However, iStockPhoto is certainly not your only option, as there are many others...

Starting with iStockPhoto, and ending with some less well-known stock photo websites, we explore a few which might be of assistance to you...

istockphoto.com is a fantastic website loved by site owners around the world. It quickly changed how people buy and sell photography and illustrations online. However, prices for the best photographs are rising, and sometimes you want something different. So, here we present a selection of alternative premium stock photo sites, plus some useful tools for finding free photos.

Getty Images was set up in 1995 by Mark Getty and Jonathan Klein. Getty Images offer the industry's best and broadest collections of imagery and footage - including award-winning news, sport and entertainment content, plus rare and contemporary archival imagery. Getty provides images for multi-million-dollar advertisers.

Dreams Time is a relatively new player with an excellent reputation. It is a member of the Picture Archive Council of America and is a popular source of photographs for many advertising agencies, magazines and media companies. Like iStockphoto, images are sold on a credit system with subscription options. Over 220,000 free photos are available under a Limited Royalty Free License, restricting you from using the idea no more than 10,000 times. Photographers donate all free images.

123 RF is another American website with a refreshing change and a great image search engine. Again, images are purchased using credits, although credits can be slightly more expensive than other options. Many photos are free for the lowest resolution or smallest size, and there's a broader range of categories than some other sites.

Shutterstock offers a monthly subscription-based service (which allows you to download up to 25 images per day) or an 'Images on Demand' plan, enabling you to download images anytime for up to one year. Shutterstock offers more than 24 million royalty-free stock images and vector illustrations. Getty Images' own Stock Exchange offers a free stock site. SXC has a long history and a great community, although it lacks choice.

Big Stock Photo has a set price based on the size of each image and offers credit packs. If you are after one or two photos, this is an excellent way to shop since you don't need to remember how the credit system works. They have an extensive selection of photographs, and although it's not the cheapest, the ordering system is slick.

Deposit Photos is another competitively priced stock photo business. Individual images can start at about 30 pence, but having a subscription brings the cost down to as little as 7 pence each. They have many illustrations, vectors and backgrounds in addition to pictures. There's also a greater depth to some categories; for example, their medicine and health section contains over 1,000 photos of operations alone.

Fotolia is a London-based business with stock photos starting from 7 pence each. Fotolia is the first worldwide social marketplace for royalty-free stock images and illustrations. They emphasise that the site is as much for designers and illustrators as for photographers, so if you are looking for graphics, this should be the first place you visit. They also have a small selection of free images.

Can Stock Photo boasts 4.5 million stock photos and is one of the few sites without membership images available on previously mentioned stock photo sites. They also have an extensive collection of vector images and illustrations.

Alamy boasts 24 million stock photos, with 15,000 new images added daily. You can tell from the start that they offer a much higher quality of photography than other sites. Images are often very well-composed, artistic and dramatic. On their homepage, they showcase some of their top photographers. You can search specifically for model-released photos too, which few sites provide. They also have a 'creative' filter with more abstract images and some illustrations.

Vector Stock offers Royalty Free Vector Art and a few Stock Images at low prices. This is one of our favourites if you are looking for a logo design or scalable vectors.

Flickr offers a vast amount of images which users uploading users have chosen to provide their work under a Creative Commons license, and you can browse or search through content under each type of license. The 'Non-Commercial Share Alike License' will allow you to copy, distribute, display, and perform the work if you credit the original author and do not use the image commercially. The 'Share Alike' license allows you to alter, transform, or build upon the work, but you may only distribute the resulting work under an identical license.