Important All media you use on your sites should be your own or in “fair public use,” usually under Creative Commons (CC) public licence. You should always credit the author when asked to do so.
Important Test your pages on multiple computers and browsers to make sure the embedded media works.
Common Downloadable Image Sources
You are probably familiar with getting images on the web, but perhaps not checking for usage rights. Most image repositories offer this filter. In Google Images, for example, select the “Tools” feature, and change the “Usage rights” filer from the dropdown.
Note This is not a guarantee of fair-use, but it does help narrow the search. You should always visit the image’s parent site to confirm with its terms, copyright, or usage guidelines.