"More than 150,000 free images and sounds." Excellent searchable archive of high quality images, clipart and more. The site is meant to be integrated with Microsoft Office, but if you are reasonably skilled at manipulating images, you should still be able to make use of the clipart in your web pages. If you don't own a Microsoft Office product and/or are having trouble making use of the MPF downloads from Microsoft's Clipart Gallery, learn about extracting media from MPF files.
Are you trying to find an image of a purple unicorn or a Zulu warrior? Maybe some Irish wallpaper or some ideas for a "Home" icon? Google images is a treasure trove of images and graphics gathered and indexed from all over the Internet. Needless to say, in a perfect world, if you wish to use someone's image, you should first attempt to get permission from the owner of that image.
Every single graphic, sprite and texture from Doom, Doom2 and Duke Nukem3D all in one spot. Some of those textures make pretty cool web page backgrounds. Also contains all sounds and music from the games.
"...the One Stop Shop for web development images!" And I'd say that just about covers it. A large assortment of bullets, buttons, icons and even a few very well done design sets. Also, an outstanding selection of quality background images aranged by category- Brushed, fabrics & weaves, marbled, paper, etc. If you click on a background swatch you can see a page displayed with that background.