Slide images need attribution

[mathie]

I nicked the first slide from here: https://www.flickr.com/photos/myfuturedotcom/6053042920 and it needs attribution to keep in with the license. I should figure out how to do that attribution...

[mathie]

Header two needs attribution too: https://commons.wikimedia.org/wiki/File:Blue_tape_measure.jpg

[mathie]

And the third slide: https://www.flickr.com/photos/marcygallery/3803517719