Free Illustrations

Hi all I'm searching some illustrations which I can use for my written part of my work. I saw that many wiring shemes are using this board for exmaple: Where do I have to ask for the permission to use it, is it avaible in a bigger resolution and are there also other illustrations which are open? Thanks already :)

That picture is from the Fritzing project. It's open source, but you should have a look at to be sure.

Perfect, thanks! With the program it's even easier to create the wiring diagrams.