In OSX, there is a built-in tool called Automator, which is found in Applications. Just open it and create an Application. When it opens, just search for rename and drag "Rename Finder Items" to the main window, which will ask you if you want a copy or not. In my case, I did not need a copy. You can change the parameters to something like below. Then save it to your Desktop for easy access.
|Inserts the year in front of the files.|