This tip is provided by the Centre for Enhancing Learning through Technology (CELT).
When searching for images using Google, use the Tools button to access the Usage rights options. Usage rights refers to way in which images are licensed for re-use or otherwise, helping you to avoid breaches of copyright law.
Of course there’s no substitute for reading the terms and conditions and license requirements when searching and using images from the Internet; but the Usage rights tool is a good starting point when sourcing images for that all important presentation!