Free access is not equivalent to open access, true open access allows you to re-use the image under a Creative Commons License. An image can be freely accessible on the web, and still under full Copyright protection. Check the Images tab for more ideas for finding open access resources using Google and other websites. Check the PDF linked below to learn how to find open access videos in YouTube.
Use Google Advanced Search to find free images or videos on the web. Select the usage rights that you need.