Well, have you heard of deviantart.com?
They make their tutorials in one image.
All you do is set the width to around 500 pixels and the height whatever it needs to be to cover the tutorial.
For example:
Here is a tutorial on creating a sig for one of my favorite games.
Note: I did not make this tutorial, it not my tutorial, I do not own the image(s) in this tutorial, all credit goes to the author of this tutorial.
http://browse.deviantart.com/?qh=&se...orial#/d27ssqt