http://www.imagecatalog.com
2. Getty Images
http://www.gettyimages.com
3. Corbis
http://www.corbis.com
4. Acclaim Images
http://www.acclaimimages.com
5. Index Open
http://www.indexopen.com
6. Index Stock Imagery
http://www.indexstock.com
7. Comstock Images
http://www.comstock.com
8. PictureQuest
http://www.picturequest.com
9. ShutterStock
http://www.shutterstock.com
10. istockphoto.com
http://www.istockphoto.com