Three questions you'll need to ask yourself when looking for images.
1. Is it really an image of X?
Pay close attention where the image is from, so you are not using an image of a different place, or a fake or altered image.
2. How can I legally use the image?
This guide discusses the licensing of images and fair use practices when using images for educational purposes.
3. How do I cite the image?
Just like any source you use, you need to give credit for the image. This guide discusses the elements to citing an image, and gives examples for APA format.
The library subscribes to a couple databases that have a great deal of "authority control," or experts tagging the images accurately. They also insure that you can use the image for educational purposes.
Free Repository of Public Domain Images
This site offer quality images that you can download, and have been tagged with the information you need to for citations.
Search for Images by Creative Commons Licensing