I found a pretty cool photo sharing site called Flickr. You can upload photos and share them with people, but the coolest feature is the ability to tag images with keywords and search other people’s albums using those tags. For example, you can search for cloud, red, piano, etc. It’s better than Google Image Search because the photos are so much better. If you don’t want everyone viewing your photos you can hide them from the public as well.
Flickr also lets you do a bunch of cool things like syndicate images (as you can see to the right of this page) and build applications like this one that generates desktop wallpapers based on the tag you enter.
The downside is that you are only allowed to upload 10MB of photos per month unless you upgrade to the pro account. If you invite 5 or more people you get a free pro account for 3 months.