Stock photography is pretty essential for web developers and designers. If your organization doesn't have a large budget for that kind of thing (stock photos are $50-$250, usually), there are a few alternatives with a decent selection — and the pictures are only a few bucks, if not free.
The best of these new, inexpensive resources is called iStock Photo. Prices are about $2, depending on the resolution you need. They have the best selection of people-pics, which are more expensive because of the model releases required. Their photos come in three sizes: those that are suitable for the web, those for small print, and high-resolution images for large-format printing jobs. www.istock.com
Another good one is the Stock Exchange, which is actually free. They have fewer pictures of people, fewer high-quality pictures and no ability to choose lower resolution. But it's free, so start your search there. http://www.sxc.hu
Another free one is the Morgue File, a "public image reference archive." Lots of old newspaper pictures that have entered the public domain. Occasionally you will find what you need here, but it doesn't have a great selection. www.morguefile.com
For more interesting backgrounds and textures and artsy work, visit: http://www.imageafter.com/
If you really need a good picture invest in something from www.corbis.com