To do a Google Image search for a photo that isn't bound by copyright, here's what you do:
First, go to www.google.com and click the Images link at the top.
Next, search for your topic. I'm searching for the lead actor in the series Sherlock.
Click Search tools
Click the drop-down menu called Usage Rights
Click "labeled for reuse"
You should now have a notification that the images you have searched for are "labeled for reuse," and should be okay for you to use.
