I ran across a website I had (stupidly) forgot about! It's an amazing resource for high quality photos for the classroom and for your websites. They have 668 MILLION photos!
Take a moment and look at Webshots by American Greetings at www.webshots.com. The photos are spectacular and searchable. You can use it free but for 19.99 a year, you get hi-res and widescreen, unlimited downloads, and no ads. Looking at the photos, I have to say I think this is a steal and I'm likely going to be signing back up again! Imagine what you can show your students in the classroom when discussing historical locations or science topics!