Free or Cheap Photos and Drawings of Buildings
Bigfoto.com
Find photos organized by geographic region or theme. The photos are free for you to use, as long as you credit the source.
ClipArt.com
A good general resource for copyright-free photos and clip art - many for free, others for a modest fee. Use the handy search function to find the buildings you need.
Corbis Online Photo Gallery
Corbis is not free, and the prices can be high. However, the photos here are very high-quality. Also, Corbis can be a good source for photos that aren't available from free and cheap photo sources.
Creative Commons Search
This handy tool lets you choose a search engine and search for Creative Commons-licensed (cc) pictures that you can legally share and reuse for free.
Flickr Creative Commons
The popular photo-sharing site Flickr lets you upload your pictures and see photos taken by others. Some photos are copyright-protected. To find the pictures that are free for you to use, search in the "creative commons" category.
Free Stock Photos
Download and use these photos at no charge, provided that you credit freestockphotos.com.
ImageAfter
Small number of architecture photos that you can download and use for free.
iStiockphoto.com
Buy royalty-free photos, vector illustrations, and video clips for very low prices. Search for great buildings by title or other key words.
morgueFile
Use the search box to find free high-resolution digital stock photography for either personal or business use.
OpenPhoto
Click on the "Architecture" link for free pictures of famous and interesting buildings.
PDPhoto
PD Photo has a good collection of free public domain photos organized by geographic region.
Stock.XCHNG
Find free photos that illustrate building parts, architectural styles, city scenes, and much more. Also upload your own photos to discuss and share.