It is important to understand image copyright when using images in your knowledge activities. You can find detailed information on copyright and acceptable use on the Wikipedia Copyright Infringement page.
Using Google's search for reusable material
One way to avoid using copyrighted material is to use Google's reuse search.
When searching for images online use Google's customized search:
Enter your search term in Google search.
Click the Images tab.
Click Tools. This will open up a new line of dropdown menus below the Tool menu.
From the dropdown Usage Rights, select Labeled for reuse. This will return images available for reuse.