Creative commons search allows you to easily query multiple databases in order to find materials that are licensed for your specific purposes.
Google Images is a valuable tool to help you find resources you can reproduce for use in online teaching or projects. To be sure that you have the rights to do so, however, you may filter the results of your searches by "usage rights" found under "search tools." This will filter results on the basis of machine-readable creative commons licenses.
Flickr is an image-based social networking site that contains billions of images. All images uploaded to Flickr are published under creative commons licenses, and so, it is easy to filter search results by the permissions you will need for your project. To do so, enter your search terms, then filter results under the "License" category. Selecting "Creative Commons Only" will remove all images from your search that are published with "all rights reserved." You may then further investigate the specific permissions granted for each image by clicking "some rights reserved."