How to find Images in the public domain, and how to protect your own

If you have ever tweeted, blogged, posted, or othewise added content to the web, you may want to embelish your work with an image of some kind.  You also may want to use an image in your promotional materials or newsletters.  The web is full of wonderful graphics and photos.  How do you know when you can reproduce the image without infringing on someone else's intellectual property rights?

Bing.

Bing has an image search with a filter for licensing.  You can choose Public Domain, Free to Use and Share, and other choices.
Very cool, and very useful.

On the flip side, if you are posting pictures, and you would like attibution, this article lists a few apps that are simple to use and customize.  Put the location and date and your name on any photos you post, and your info will always appear if the photos are reposted.