On my travels over the internet I found another tool which has copyright free images which can be used in classrooms. http://www.iconfinder.com/ – It has a variety of icons on a lot of different subject matters.
My previous post with other links can be found at https://ictintheclassroom.edublogs.org/2013/02/05/digital-citizenship-images-you-can-use-in-the-classroom/
Enjoy